S-3

Large accelerated filer

Accelerated filer

Non-accelerated filer

Smaller reporting company

Emerging growth company

S-3 1 d44885ds3.htm S-3 S-3

As filed with the Securities and Exchange Commission on April 9, 2026

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

AN2 Therapeutics, Inc.

(Exact name of registrant as specified in its charter)

Delaware

82-0606654

(State or other jurisdiction of

incorporation or organization)

(I.R.S. Employer

Identification Number)

1300 El Camino Real, Suite 100

Menlo Park, California 94025

(650) 331-9090

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Eric Easom

President and Chief Executive Officer

1300 El Camino Real, Suite 100

Menlo Park, California 94025

(650) 331-9090

(Address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Kathleen M. Wells

Richard Kim

Latham & Watkins LLP

140 Scott Drive

Menlo Park, California 94025

(650) 328-4600

Joshua Eizen

Chief Legal Officer and Chief Operating Officer

1300 El Camino Real, Suite 100

Menlo Park, California 94025

(650) 331-9090

APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: From time to time after the effective date of this registration statement.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box. ☐

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box. ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective on filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box. ☐

this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of Securities Act. ☐

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the registration statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

EXPLANATORY NOTE

This registration statement (this “Registration Statement”) contains the following documents:

•

a base prospectus covering the offering, issuance and sale by AN2 Therapeutics, Inc. (“we,” “our” or “us”) of up to a maximum aggregate offering price of $300,000,000 of the securities identified therein from time to time in one or more offerings and the offering and sale of up to an aggregate of 14,035,104 shares of common stock by selling securityholders;

•

a sales agreement prospectus supplement covering the offering, issuance and sale by us of up to a maximum aggregate offering price of $80,000,000 of our common stock that may be offered, issued and sold from time to time under an open market sale agreement, dated April 9, 2026, with Jefferies LLC; and

•

a resale prospectus supplement covering the potential resale by the selling securityholders named therein of the 14,035,104 shares of our common stock referenced in the base prospectus.

The base prospectus immediately follows this explanatory note. The specific terms of any securities to be offered pursuant to the base prospectus will be specified in a prospectus supplement to the base prospectus.

The sales agreement prospectus supplement immediately follows the base prospectus. The common stock that may be offered, issued and sold by us under the sales agreement prospectus supplement is included in the $300,000,000 of securities that may be offered, issued and sold by us under the base prospectus. Upon termination of the sales agreement, any portion of the $80,000,000 included in the sales agreement prospectus supplement that is not sold pursuant to the sales agreement will be available for sale in other offerings pursuant to the base prospectus and a corresponding prospectus supplement.

The resale prospectus supplement immediately follows the sales agreement prospectus supplement.

This Registration Statement is being filed pursuant to Rule 415(a)(6) under the Securities Act of 1933, as amended (the “Securities Act”), to replace our registration statement on Form S-3 (File No. 333-271174), filed with the Securities and Exchange Commission on April 6, 2023 (the “Expiring Registration Statement”), which is due to expire on April 13, 2026.

Pursuant to Rule 415(a)(5)(ii) under the Securities Act, by filing this Registration Statement, we may issue and sell securities covered by the Expiring Registration Statement until the earlier of the effective date of this Registration Statement or 180 days after April 13, 2026. Pursuant to Rule 415(a)(6) under the Securities Act, the securities registered pursuant to this Registration Statement include an aggregate of $209,983,747.80 of unsold securities (the “Unsold Securities”) previously registered under the Expiring Registration Statement, and the filing fee of $23,140.21 associated therewith (which amount is based on the filing fee rate in effect at the time of the filing of the Expiring Registration Statement) is hereby carried forward to be applied to the Unsold Securities and no additional filing fee is due with respect to such Unsold Securities in connection with the filing of this Registration Statement. In accordance with Rule 415(a)(6), the effectiveness of this Registration Statement will be deemed to terminate the Expiring Registration Statement.

The information in this preliminary prospectus is not complete and may be changed. These securities may not be sold until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell nor does it seek an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

Subject to Completion, dated April 9, 2026

PROSPECTUS

LOGO

AN2 Therapeutics, Inc.

$300,000,000

Common Stock

Preferred Stock

Debt Securities

Warrants

Units

14,035,104 Shares of

Common Stock

Offered by the Selling Securityholders

We may offer and sell up to $300,000,000 in the aggregate of the securities identified above, and the selling securityholders may offer and sell up to an aggregate of 14,035,104 shares of common stock identified above, in each case from time to time in one or more offerings. This prospectus provides you with a general description of the securities. We will not receive any proceeds from the sale of our common stock by the selling securityholders.

Each time we offer and sell securities, we will provide a supplement to this prospectus that contains specific information about the offering and the amounts, prices and terms of the securities. In addition, in connection with certain offers and sales of securities by the selling securityholders, we and the selling securityholders will provide, if applicable, a prospectus supplement to this prospectus containing specific information about the offering by the selling securityholders and the amounts, prices and terms of the securities being offered. The supplement may also add, update or change information contained in this prospectus with respect to that offering. You should carefully read this prospectus and the applicable prospectus supplement before you invest in any of our securities.

We may offer and sell the securities described in this prospectus and any prospectus supplement to or through one or more underwriters, dealers and agents, or directly to purchasers, or through a combination of these methods. In addition, the selling securityholders may offer and sell shares of our common stock from time to time, together or separately. If any underwriters, dealers or agents are involved in the sale of any of the securities, their names and any applicable purchase price, fee, commission or discount arrangement between or among them will be set forth, or will be calculable from the information set forth, in the applicable prospectus supplement. See the sections of this prospectus entitled “About this Prospectus” and “Plan of Distribution” for more information. No securities may be sold without delivery of this prospectus and the applicable prospectus supplement describing the method and terms of the offering of such securities.

INVESTING IN OUR SECURITIES INVOLVES RISKS. SEE THE “RISK FACTORS” ON PAGE 7 OF THIS PROSPECTUS AND ANY SIMILAR SECTION CONTAINED IN THE APPLICABLE PROSPECTUS SUPPLEMENT CONCERNING FACTORS YOU SHOULD CONSIDER BEFORE INVESTING IN OUR SECURITIES.

Our common stock is listed on the Nasdaq Global Select Market under the symbol “ANTX.” On April 8, 2026, the last reported sale price of our common stock on the Nasdaq Global Select Market was $3.34 per share.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is , 2026.

TABLE OF CONTENTS


ABOUT THIS PROSPECTUS			1
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS			2
WHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE			4
THE COMPANY			6
RISK FACTORS			7
USE OF PROCEEDS			8
DESCRIPTION OF CAPITAL STOCK			9
DESCRIPTION OF DEBT SECURITIES			13
DESCRIPTION OF WARRANTS			21
DESCRIPTION OF UNITS			23
GLOBAL SECURITIES			24
SELLING SECURITYHOLDERS			28
PLAN OF DISTRIBUTION			29
LEGAL MATTERS			31
EXPERTS			31

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the U.S. Securities and Exchange Commission (the “SEC”), using a “shelf” registration process. By using a shelf registration statement, we may sell securities from time to time and in one or more offerings up to a total dollar amount of $300,000,000 and the selling securityholders to be named in a supplement to this prospectus may, from time to time, sell up to 14,035,104 shares of common stock from time to time in one or more offerings as described in this prospectus. Each time that we or the selling securityholders offer and sell securities, we or the selling securityholders will provide a prospectus supplement to this prospectus that contains specific information about the securities being offered and sold and the specific terms of that offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. The prospectus supplement or free writing prospectus may also add, update or change information contained in this prospectus with respect to that offering. If there is any inconsistency between the information in this prospectus and the applicable prospectus supplement or free writing prospectus, you should rely on the prospectus supplement or free writing prospectus, as applicable. Before purchasing any securities, you should carefully read both this prospectus and the applicable prospectus supplement (and any applicable free writing prospectuses), together with the additional information described under the heading “Where You Can Find More Information; Incorporation by Reference.”

Neither we, nor the selling securityholders, have authorized anyone to provide you with any information or to make any representations other than those contained in this prospectus, any applicable prospectus supplement or any free writing prospectuses prepared by or on behalf of us or to which we have referred you. We and the selling securityholders take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We and the selling securityholders will not make an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus and the applicable prospectus supplement to this prospectus is accurate only as of the date on its respective cover, that the information appearing in any applicable free writing prospectus is accurate only as of the date of that free writing prospectus, and that any information incorporated by reference is accurate only as of the date of the document incorporated by reference, unless we indicate otherwise. Our business, financial condition, results of operations and prospects may have changed since those dates. This prospectus incorporates by reference, and any prospectus supplement or free writing prospectus may contain and incorporate by reference, market data and industry statistics and forecasts that are based on independent industry publications and other publicly available information. Although we believe these sources are reliable, we do not guarantee the accuracy or completeness of this information and we have not independently verified this information. In addition, the market and industry data and forecasts that may be included or incorporated by reference in this prospectus, any prospectus supplement or any applicable free writing prospectus may involve estimates, assumptions and other risks and uncertainties and are subject to change based on various factors, including those discussed under the heading “Risk Factors” contained in this prospectus, the applicable prospectus supplement and any applicable free writing prospectus, and under similar headings in other documents that are incorporated by reference into this prospectus. Accordingly, investors should not place undue reliance on this information.

When we refer to “AN2,” “AN2 Therapeutics,” “we,” “our,” “us” and the “Company” in this prospectus, we mean AN2 Therapeutics, Inc., unless otherwise specified. When we refer to “you,” we mean the potential holders of the applicable series of securities.

This prospectus also includes trademarks, tradenames, and service marks that are the property of us or other organizations. Solely for convenience, trademarks and tradenames referred to in this prospectus appear without the ^® or ^™ symbols, but those references are not intended to indicate, in any way, that we will not assert, to the fullest extent under applicable law, our rights, or the right of the applicable owner will not assert its rights to these trademarks and tradenames.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents we have filed with the SEC that are incorporated by reference contain “forward-looking statements” within the meaning of Section 27A of the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). All statements other than statements of historical facts contained in this prospectus, including any statements regarding our future results of operations and financial position, business strategy, product candidates, planned preclinical and nonclinical studies and clinical trials, results of preclinical and nonclinical studies, clinical trials, research and development costs, regulatory approvals, timing and likelihood of success, as well as plans and objectives of management for future operations, are forward-looking statements. These statements involve known and unknown risks, uncertainties, and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance, or achievements expressed or implied by the forward-looking statements.

In some cases, you can identify forward-looking statements by terms such as “will,” “may,” “should,” “expects,” “might,” “plans,” “anticipates,” “could,” “intends,” “target,” “projects,” “contemplates,” “believes,” “estimates,” “predicts,” “potential,” “seek,” “would” or “continue,” or the negative of these terms or other similar expressions. Forward-looking statements may include, but are not limited to, statements about:

•

the initiation, timing, progress, and results of our preclinical and nonclinical studies and clinical trials, and our research and development programs, including the manufacture of clinical trial material and drug product for launch;

•

the sufficiency of our existing cash to fund our future operating expenses and capital expenditure requirements;

•

the accuracy of our estimates regarding expenses, capital requirements and needs for additional financing;

•

our use of the net proceeds from financing activities;

•

the ability of our ongoing and planned clinical trials to be sufficient for regulatory approval in the United States and other territories;

•

our ability to commence studies of epetraborole in additional patient populations, which regulatory authorities may not allow or authorize or may delay allowing or authorizing;

•

the translation of our preclinical results and data and early clinical trial results, in particular relating to safety, efficacy and durability, into future clinical trial results;

•

our ability to retain the continued service of our key professionals and to identify, hire, and retain additional qualified professionals;

•

our ability to advance our initial product candidates and any other product candidates we may develop into, and successfully complete, clinical trials;

•

the timing of and our ability to obtain and maintain regulatory approvals for our initial product candidates and any other product candidates we may develop;

•

the commercialization of our initial product candidates and any other product candidates we may develop, if approved;

•

the ability of epetraborole, if approved, to successfully compete with other therapies, including therapies currently in development;

•

the size of the market opportunity for epetraborole or any other product candidates we may develop in each of the diseases we target;

•

the pricing, coverage, and reimbursement of epetraborole, if approved;

•

the implementation of our business model, strategic plans for our business, and our initial product candidates and any other product candidates we may develop;

•

the scope of protection we are able to establish and maintain for intellectual property rights covering epetraborole and any other product candidates;

•

our ability to identify additional product candidates and advance them into clinical development;

•

our financial performance;

•

developments relating to our competitors and our industry;

•

our expectations regarding the impact of inflation, macroeconomic conditions and geopolitical conflicts on our business and operations, including on our manufacturing suppliers, collaborators, contract research organizations (“CROs”) and employees; and

•

our expectations regarding the period during which we will qualify as an emerging growth company under the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”).

We have based these forward-looking statements largely on our current expectations and projections about our business, the industry in which we operate and financial trends that we believe may affect our business, financial condition, results of operations, and prospects and these forward-looking statements are not guarantees of future performance or development. These forward-looking statements are subject to a number of risks, uncertainties, and assumptions. We discuss in greater detail many of these risks, uncertainties, and assumptions under the heading “Risk Factors” contained in this prospectus and the documents incorporated by reference, and in our most recent Annual Report on Form 10-K and in our most recent Quarterly Report on Form 10-Q, as updated by our subsequent filings with the SEC, which are incorporated by reference into this prospectus in their entirety. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified, you should not rely on these forward-looking statements as predictions of future events. The events and circumstances reflected in our forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the forward-looking statements. Also, these forward-looking statements represent our estimates and assumptions only as of the date of the document containing the applicable statement. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, or otherwise.

In addition, statements that “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this prospectus, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain, and you are cautioned not to unduly rely upon these statements.

WHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE

Available Information

We file reports, proxy statements and other information with the SEC. The SEC maintains a website that contains reports, proxy and information statements and other information about issuers, such as us, who file electronically with the SEC. The address of that website is http://www.sec.gov.

Our website address is https://www.an2therapeutics.com/. The information on our website, however, is not, and should not be deemed to be, a part of this prospectus.

This prospectus and any prospectus supplement are part of a registration statement that we filed with the SEC and do not contain all of the information in the registration statement. The full registration statement may be obtained from the SEC or us, as provided below. Forms of the indenture and other documents establishing the terms of the offered securities are or may be filed as exhibits to the registration statement or documents incorporated by reference in the registration statement. Statements in this prospectus or any prospectus supplement about these documents are summaries and each statement is qualified in all respects by reference to the document to which it refers. You should refer to the actual documents for a more complete description of the relevant matters. You may inspect a copy of the registration statement through the SEC’s website, as provided above.

Incorporation by Reference

The SEC’s rules allow us to “incorporate by reference” information into this prospectus, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is deemed to be part of this prospectus, and subsequent information that we file with the SEC will automatically update and supersede that information. Any statement contained in this prospectus or a previously filed document incorporated by reference will be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in this prospectus or a subsequently filed document incorporated by reference modifies or replaces that statement.

This prospectus and any accompanying prospectus supplement incorporate by reference the documents set forth below that have previously been filed with the SEC:

•

Our Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the SEC on March 17, 2026.

•

The information specifically incorporated by reference into our Annual Report on Form 10-K for the fiscal year ended December 31, 2024 from our Definitive Proxy Statement on Schedule 14A, filed with the SEC on April 10, 2025.

•

Our Current Reports on Form 8-K filed (other than information furnished rather than filed) with the SEC on January 29, 2026, March 10, 2026, March 20, 2026 and April 9, 2026.

•

The description of our common stock which is contained in our Registration Statement on Form 8-A filed on March 22, 2022 (File No. 001-41331) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), as updated by Exhibit 4.3 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the SEC on March 17, 2026, including any amendment or report filed for the purpose of updating such description.

All reports and other documents we subsequently file pursuant to Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, which we refer to as the “Exchange Act” in this prospectus, prior to the termination of this offering, including all such documents we may file with the SEC after the date of the initial registration statement and prior to the effectiveness of the registration statement, but excluding any

information furnished to, rather than filed with, the SEC, will also be incorporated by reference into this prospectus and deemed to be part of this prospectus from the date of the filing of such reports and documents.

You may request a free copy of any of the documents incorporated by reference in this prospectus by writing or telephoning us at the following address:

AN2 Therapeutics, Inc.

Attn: Chief Legal Officer

1300 El Camino Real, Suite 100

Menlo Park, California 94025

(650) 331-9090

Exhibits to the filings will not be sent, however, unless those exhibits have specifically been incorporated by reference in this prospectus or any accompanying prospectus supplement.

THE COMPANY

Overview

We are a clinical stage biopharmaceutical company focused on the discovery and development of novel small-molecule therapeutics derived from our boron chemistry platform. Our development pipeline spans hematologic diseases, infectious diseases, and oncology, as well as advanced research programs focused on targets in oncology, bone disorders, and infectious diseases. We are committed to delivering high-impact drugs to patients that address critical unmet needs and improve health outcomes.

Corporate Information

We were incorporated in February 2017 as a Delaware corporation and launched operations in November 2019. Our principal executive offices are located at 1300 El Camino Real, Suite 100, Menlo Park, California 94025 and our telephone number is (650) 331-9090. Our website address is www.an2therapeutics.com. The information contained on, or that can be accessed through, our website will not be deemed to be incorporated by reference into this prospectus and does not constitute part of this prospectus. Our website address is included in this prospectus as an inactive textual reference only.

We use the AN2 Therapeutics logo and other marks as trademarks in the United States and other countries. This prospectus contains references to our trademarks and service marks and to those belonging to other entities. Solely for convenience, trademarks and trade names referred to in this prospectus, including logos, artwork, and other visual displays, may appear without the ^® or ^™ symbols, but such references are not intended to indicate in any way that the respective owners will not assert, to the fullest extent under applicable law, their rights or the rights of the applicable licensor to these trademarks and trade names. We do not intend our use or display of other entities’ trade names, trademarks, or service marks to imply a relationship with, or endorsement or sponsorship of us by, any other entity.

RISK FACTORS

Investment in any securities offered pursuant to this prospectus and the applicable prospectus supplement involves risks. Before deciding whether to invest in our securities, you should carefully consider the risk factors incorporated by reference to our most recent Annual Report on Form 10-K and any subsequent Quarterly Reports on Form 10-Q or Current Reports on Form 8-K, and all other information contained or incorporated by reference into this prospectus, as updated by our subsequent filings under the Exchange Act, and the risk factors and other information contained in the applicable prospectus supplement and any applicable free writing prospectus. The occurrence of any of these risks might cause you to lose all or part of your investment in the offered securities. There may be other unknown or unpredictable economic, business, competitive, regulatory or other factors that could have material adverse effects on our future results. Past financial performance may not be a reliable indicator of future performance, and historical trends should not be used to anticipate results or trends in future periods. If any of these risks actually occurs, our business, financial condition, results of operations or cash flow could be seriously harmed. This could cause the trading price of our securities to decline, resulting in a loss of all or part of your investment. Please also carefully read the section entitled “Cautionary Note Regarding Forward-Looking Statements” included in our most recent Annual Report on Form 10-K and any subsequent Quarterly Reports on Form 10-Q or Current Reports on Form 8-K.

USE OF PROCEEDS

We intend to use the net proceeds from the sale of the securities as set forth in the applicable prospectus supplement. We will not receive any of the proceeds from the sale of common stock being offered by any of the selling securityholders.

DESCRIPTION OF CAPITAL STOCK

The following description of our capital stock is a summary. This summary is subject to the General Corporation Law of the State of Delaware (the “DGCL”) and the complete text of our amended and restated certificate of incorporation, as amended by the Certificate of Designations of Series A Junior Participating Preferred Stock (collectively, the “Restated Certificate”), and amended and restated bylaws (the “Bylaws”), both of which are exhibits to this prospectus.

Authorized Capital Shares

Our authorized capital stock consists of 500,000,000 shares of common stock, par value $0.00001 per share, and 10,000,000 shares of preferred stock, par value $0.00001 per share. 500,000 shares of our preferred stock are designated as Series A Junior Participating Preferred Stock.

Common Stock

Voting Rights

The common stock is entitled to one vote per share on any matter that is submitted to a vote of our stockholders. Our Restated Certificate does not provide for cumulative voting for the election of directors. Our Restated Certificate establishes a classified board of directors that is divided into three classes with staggered three-year terms. Only the directors in one class will be subject to election by a plurality of the votes cast at each annual meeting of our stockholders, with the directors in the other classes continuing for the remainder of their respective three-year terms. The affirmative vote of holders of at least 66 2/3% of the voting power of all of the then-outstanding shares of capital stock, voting as a single class, will be required to amend certain provisions of our Restated Certificate, including provisions relating to amending our Bylaws, the classified structure of our board of directors, the size of our board of directors, removal of directors, director liability, vacancies on our board of directors, special meetings, stockholder notices, actions by written consent and exclusive jurisdiction.

Economic Rights

Except as otherwise expressly provided in our Restated Certificate or required by applicable law, all shares of our common stock have the same rights and privileges and rank equally, share ratably and be identical in all respects for all matters, including those described below.

Dividends. Subject to preferences that may apply to any shares of preferred stock outstanding at the time, the holders of our common stock are entitled to receive dividends out of funds legally available if our board of directors, in its discretion, determines to issue dividends and then only at the times and in the amounts that our board of directors may determine.

Liquidation Rights. On our liquidation, dissolution, or winding-up, the holders of our common stock will be entitled to share equally, identically, and ratably in all assets remaining after the payment of any liabilities, liquidation preferences, and accrued or declared but unpaid dividends, if any, with respect to any outstanding preferred stock, unless a different treatment is approved by the affirmative vote of the holders of a majority of the outstanding shares of such affected class, voting separately as a class.

No Preemptive or Similar Rights

The holders of shares of our common stock are not entitled to preemptive rights, and are not subject to conversion, redemption, or sinking fund provisions.

Preferred Stock

Our board of directors may, without further action by our stockholders, fix the rights, preferences, privileges and

restrictions of up to 10,000,000 shares of preferred stock in one or more series and authorize their issuance. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences and the number of shares constituting any series or the designation of such series, any or all of which may be greater than the rights of common stock. Any issuance of preferred stock could adversely

affect the voting power of holders of common stock and the likelihood that such holders would receive dividend payments and payments on liquidation. In addition, the issuance of preferred stock could have the effect of delaying, deterring or preventing a change of control or other corporate action. 500,000 shares of our preferred stock are designated as Series A Junior Participating Preferred Stock.

Anti-Takeover Provisions

The provisions of Delaware law, our Restated Certificate, and our Bylaws, which are summarized below, may have the effect of delaying, deferring, or discouraging another person from acquiring control of our company. They are also designed, in part, to encourage persons seeking to acquire control of us to negotiate first with our board of directors. We believe that the benefits of increased protection of our potential ability to negotiate with an unfriendly or unsolicited acquirer outweigh the disadvantages of discouraging a proposal to acquire us because negotiation of these proposals could result in an improvement of their terms.

Restated Certificate and Bylaws

Our Restated Certificate and our Bylaws also provide that all stockholder actions are required to be taken by a vote of the stockholders at a duly called annual or special meeting, and that stockholders may not take any action by written consent in lieu of a meeting. According to our Bylaws, a special meeting of stockholders may only be called by a majority of our board of directors, the chair of our board of directors, or our chief executive officer or president. Our Bylaws establish an advance notice procedure for stockholder proposals to be brought before an annual meeting of our stockholders, including proposed nominations of persons for election to our board of directors.

Our Restated Certificate provides for the division of our board of directors into three classes serving staggered three-year terms, with one class being elected each year. Our Restated Certificate also provides that directors may be removed only for cause by the affirmative vote of the holders of at least 66 2/3% of the shares then entitled to vote at an annual election of directors. Furthermore, any vacancy on our board of directors, however occurring, including a vacancy resulting from an increase in the size of our board, may be filled by the affirmative vote of a majority of our directors then in office even if less than a quorum.

The foregoing provisions make it more difficult for another party to obtain control of us by replacing our board of directors. Since our board of directors has the power to retain and discharge our officers, these provisions could also make it more difficult for existing stockholders or another party to effect a change in management. In addition, the authorization of undesignated preferred stock makes it possible for our board of directors to issue preferred stock with voting or other rights or preferences that could impede the success of any attempt to change our control.

These provisions are designed to reduce our vulnerability to an unsolicited acquisition proposal and to discourage certain tactics that may be used in proxy fights. However, such provisions could have the effect of discouraging others from making tender offers for our shares and may have the effect of deterring hostile takeovers or delaying changes in our control or management. As a consequence, these provisions may also inhibit fluctuations in the market price of our stock that could result from actual or rumored takeover attempts.

Section 203 of the Delaware General Corporation Law

We are subject to the provisions of Section 203 of the DGCL (“Section 203”). In general, Section 203 prohibits a publicly-held Delaware corporation from engaging in any business combination with any interested stockholder for a period of three years after the date that such stockholder became an interested stockholder, subject to certain exceptions. A “business combination” includes, among other things, a merger, asset or stock sale or other transaction resulting in a financial benefit to the interested stockholder. An “interested stockholder” is a person who, together with affiliates and associates, owns, or did own within three years prior to the determination of interested stockholder status, 15% or more of the corporation’s voting stock.

Choice of Forum

Our Restated Certificate provides that, unless we consent in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware (or, if and only if the Court of Chancery of the State of Delaware lacks subject matter jurisdiction, any state court located within the State of Delaware or, if and only if all such state courts lack subject matter jurisdiction, the federal district court for the District of Delaware) and any appellate court therefrom is the sole and exclusive forum for the following claims or causes of action under the Delaware statutory or common law: (i) any derivative claim or cause of action brought on our behalf; (ii) any claim or cause of action for a breach of fiduciary duty owed by any of our current or former directors, officers or other employees to us or our stockholders; (iii) any claim or cause of action against us or any of our current or former directors, officers or other employees arising out of or pursuant to any provision of the DGCL, our Restated Certificate, or our Bylaws (as each may be amended from time to time); (iv) any claim or cause of action seeking to interpret, apply, enforce or determine the validity of our Restated Certificate or our Bylaws (as each may be amended from time to time, including any right, obligation, or remedy thereunder); (v) any claim or cause of action as to which the DGCL confers jurisdiction to the Court of Chancery of the State of Delaware; and (vi) any claim or cause of action against us or any of our current or former directors, officers or other employees governed by the internal-affairs doctrine, in all cases to the fullest extent permitted by law and subject to the court’s having personal jurisdiction over the indispensable parties named as defendants. Our Restated Certificate further provides that, unless we consent in writing to the selection of an alternative forum, to the fullest extent permitted by law, the federal district courts of the United States will be the exclusive forum for resolving any complaint asserting a cause or causes of action arising under the Securities Act, including all causes of action asserted against a defendant to such complaint. The choice of forum provisions would not apply to claims or causes of action brought to enforce a duty or liability created by the Exchange Act or any other claim for which the federal courts have exclusive jurisdiction.

For the avoidance of doubt, these provisions are intended to benefit and may be enforced by us, our officers and directors, the underwriters to any offering giving rise to such complaint, and any other professional entity whose profession gives authority to a statement made by that person or entity and who has prepared or certified any part of the documents underlying the offering. While the Delaware courts have determined that such choice of forum provisions are facially valid, a stockholder may nevertheless seek to bring a claim in a venue other than those designated in the exclusive forum provisions, and there can be no assurance that such provisions will be enforced by a court in those other jurisdictions. We note that investors cannot waive compliance with the federal securities laws and the rules and regulations thereunder.

Additionally, our Restated Certificate provides that any person or entity holding, owning or otherwise acquiring any interest in any of our securities shall be deemed to have notice of and consented to these provisions. These choice of forum provisions may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with us or any of our directors, officers, other employees or stockholders, which may discourage lawsuits with respect to such claims, although our stockholders will not be deemed to have waived our compliance with federal securities laws and the rules and regulations thereunder.

Limitations on Liability and Indemnification

Our Restated Certificate contains provisions that limit the liability of our directors and officers for monetary damages to the fullest extent permitted by Delaware law. Consequently, our directors and officers will not be personally liable to us or our stockholders for monetary damages for any breach of fiduciary duties as directors or officers, except liability of:

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a director or an officer for any breach of the director’s or officer’s duty of loyalty to us or its stockholders;

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a director or an officer for any act or omission not in good faith or that involves intentional misconduct or a knowing violation of law;

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a director pursuant to Section 174 of the DGCL;

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a director or an officer for any transaction from which the director or officer derived an improper personal benefit; or

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an officer in any action by or in the right of us.

Such limitation of liability does not apply to liabilities arising under federal securities laws and does not affect the availability of equitable remedies such as injunctive relief or rescission.

Our Restated Certificate authorizes us to indemnify our directors, officers, employees and other agents to the fullest extent permitted by Delaware law. Each of our Restated Certificate and Bylaws provide that we are required to indemnify our directors and officers, in each case to the fullest extent permitted by Delaware law and may indemnify our other employees and agents. Our Bylaws also obligate us to, on satisfaction of certain conditions, advance expenses incurred by a director or officer in advance of the final disposition of any action or proceeding, and permit us to secure insurance on behalf of any officer, director, employee, or other agent for any liability arising out of his or her actions in that capacity regardless of whether we would otherwise be permitted to indemnify him or her under the provisions of Delaware law. We have entered and expect to continue to enter into agreements to indemnify our directors, executive officers and other employees as determined by our board of directors. With specified exceptions, these agreements provide for indemnification for related expenses including, among other things, attorneys’ fees, judgments, fines and settlement amounts incurred by any of these individuals in any action or proceeding. We believe that these bylaw provisions and indemnification agreements are necessary to attract and retain qualified persons as directors and officers. We also maintain directors’ and officers’ liability insurance.

The limitation of liability and indemnification provisions in our Restated Certificate and Bylaws may discourage stockholders from bringing a lawsuit against our directors and officers for breach of their fiduciary duty. They may also reduce the likelihood of derivative litigation against our directors and officers, even though an action, if successful, might benefit us and our stockholders. Further, a stockholder’s investment may be adversely affected to the extent that we pay the costs of settlement and damages.

Exchange Listing

Our common stock is listed on The Nasdaq Global Select Market under the symbol “ANTX.”

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Equiniti Trust Company, LLC. The transfer agent’s address is 28 Liberty Street, 53rd Floor, New York, NY 10005.

DESCRIPTION OF DEBT SECURITIES

The following description, together with the additional information we include in any applicable prospectus supplement or free writing prospectus, summarizes certain general terms and provisions of the debt securities that we may offer under this prospectus. When we offer to sell a particular series of debt securities, we will describe the specific terms of the series in a supplement to this prospectus. We will also indicate in the supplement to what extent the general terms and provisions described in this prospectus apply to a particular series of debt securities.

We may issue debt securities either separately, or together with, or upon the conversion or exercise of or in exchange for, other securities described in this prospectus. Debt securities may be our senior, senior subordinated or subordinated obligations and, unless otherwise specified in a supplement to this prospectus, the debt securities will be our direct, unsecured obligations and may be issued in one or more series.

The debt securities will be issued under an indenture between us and a third party to be identified therein, as trustee. We have summarized select portions of the indenture below. The summary is not complete. The form of the indenture has been filed as an exhibit to the registration statement and you should read the indenture for provisions that may be important to you. In the summary below, we have included references to the section numbers of the indenture so that you can easily locate these provisions. Capitalized terms used in the summary and not defined herein have the meanings specified in the indenture.

As used in this section only, “AN2 Therapeutics,” “we,” “our” or “us” refer to AN2 Therapeutics, Inc. excluding our subsidiaries, unless expressly stated or the context otherwise requires.

General

The terms of each series of debt securities will be established by or pursuant to a resolution of our board of directors and set forth or determined in the manner provided in a resolution of our board of directors, in an officer’s certificate or by a supplemental indenture. (Section 2.2) The particular terms of each series of debt securities will be described in a prospectus supplement relating to such series (including any pricing supplement or term sheet).

We can issue an unlimited amount of debt securities under the indenture that may be in one or more series with the same or various maturities, at par, at a premium, or at a discount. (Section 2.1) We will set forth in a prospectus supplement (including any pricing supplement or term sheet) relating to any series of debt securities being offered, the aggregate principal amount and the following terms of the debt securities, if applicable:

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the title and ranking of the debt securities (including the terms of any subordination provisions);

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the price or prices (expressed as a percentage of the principal amount) at which we will sell the debt securities;

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any limit on the aggregate principal amount of the debt securities;

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the date or dates on which the principal of the securities of the series is payable;

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the rate or rates (which may be fixed or variable) per annum or the method used to determine the rate or rates (including any commodity, commodity index, stock exchange index or financial index) at which the debt securities will bear interest, the date or dates from which interest will accrue, the date or dates on which interest will commence and be payable and any regular record date for the interest payable on any interest payment date;

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the place or places where principal of, and interest, if any, on the debt securities will be payable (and the method of such payment), where the securities of such series may be surrendered for registration of transfer or exchange, and where notices and demands to us in respect of the debt securities may be delivered;

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the period or periods within which, the price or prices at which and the terms and conditions upon which we may redeem the debt securities;

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any obligation we have to redeem or purchase the debt securities pursuant to any sinking fund or analogous provisions or at the option of a holder of debt securities and the period or periods within which, the price or prices at which and in the terms and conditions upon which securities of the series shall be redeemed or purchased, in whole or in part, pursuant to such obligation;

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the dates on which and the price or prices at which we will repurchase debt securities at the option of the holders of debt securities and other detailed terms and provisions of these repurchase obligations;

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the denominations in which the debt securities will be issued, if other than denominations of $1,000 and any integral multiple thereof;

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whether the debt securities will be issued in the form of certificated debt securities or global debt securities;

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the portion of principal amount of the debt securities payable upon declaration of acceleration of the maturity date, if other than the principal amount;

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the currency of denomination of the debt securities, which may be United States Dollars or any foreign currency, and if such currency of denomination is a composite currency, the agency or organization, if any, responsible for overseeing such composite currency;

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the designation of the currency, currencies or currency units in which payment of principal of, premium and interest on the debt securities will be made;

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if payments of principal of, premium or interest on the debt securities will be made in one or more currencies or currency units other than that or those in which the debt securities are denominated, the manner in which the exchange rate with respect to these payments will be determined;

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the manner in which the amounts of payment of principal of, premium, if any, or interest on the debt securities will be determined, if these amounts may be determined by reference to an index based on a currency or currencies or by reference to a commodity, commodity index, stock exchange index or financial index;

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any provisions relating to any security provided for the debt securities;

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any addition to, deletion of or change in the Events of Default described in this prospectus or in the indenture with respect to the debt securities and any change in the acceleration provisions described in this prospectus or in the indenture with respect to the debt securities;

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any addition to, deletion of or change in the covenants described in this prospectus or in the indenture with respect to the debt securities;

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any depositaries, interest rate calculation agents, exchange rate calculation agents or other agents with respect to the debt securities;

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the provisions, if any, relating to conversion or exchange of any debt securities of such series, including if applicable, the conversion or exchange price and period, provisions as to whether conversion or exchange will be mandatory, the events requiring an adjustment of the conversion or exchange price and provisions affecting conversion or exchange;

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any other terms of the debt securities, which may supplement, modify or delete any provision of the indenture as it applies to that series, including any terms that may be required under applicable law or regulations or advisable in connection with the marketing of the securities; and

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whether any of our direct or indirect subsidiaries will guarantee the debt securities of that series, including the terms of subordination, if any, of such guarantees. (Section 2.2)

We may issue debt securities that provide for an amount less than their stated principal amount to be due and payable upon declaration of acceleration of their maturity pursuant to the terms of the indenture. We will provide you with information on the federal income tax considerations and other special considerations applicable to any of these debt securities in the applicable prospectus supplement.

If we denominate the purchase price of any of the debt securities in a foreign currency or currencies or a foreign currency unit or units, or if the principal of and any premium and interest on any series of debt securities is payable in a foreign currency or currencies or a foreign currency unit or units, we will provide you with information on the restrictions, elections, general tax considerations, specific terms and other information with respect to that issue of debt securities and such foreign currency or currencies or foreign currency unit or units in the applicable prospectus supplement.

Transfer and Exchange

Each debt security will be represented by either one or more global securities registered in the name of The Depository Trust Company (the “Depositary”), or a nominee of the Depositary (we will refer to any debt security represented by a global debt security as a “book-entry debt security”), or a certificate issued in definitive registered form (we will refer to any debt security represented by a certificated security as a “certificated debt security”) as set forth in the applicable prospectus supplement. Except as set forth under the heading “Global Debt Securities and Book-Entry System” below, book-entry debt securities will not be issuable in certificated form.

Certificated Debt Securities. You may transfer or exchange certificated debt securities at any office we maintain for this purpose in accordance with the terms of the indenture. (Section 2.4) No service charge will be made for any transfer or exchange of certificated debt securities, but we may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection with a transfer or exchange. (Section 2.7)

You may effect the transfer of certificated debt securities and the right to receive the principal of, premium and interest on certificated debt securities only by surrendering the certificate representing those certificated debt securities and either reissuance by us or the trustee of the certificate to the new holder or the issuance by us or the trustee of a new certificate to the new holder.

Global Debt Securities and Book-Entry System. Each global debt security representing book-entry debt securities will be deposited with, or on behalf of, the Depositary, and registered in the name of the Depositary or a nominee of the Depositary. Please see “Global Securities.”

Covenants

We will set forth in the applicable prospectus supplement any restrictive covenants applicable to any issue of debt securities. (Article IV)

No Protection in the Event of a Change of Control

Unless we state otherwise in the applicable prospectus supplement, the debt securities will not contain any provisions which may afford holders of the debt securities protection in the event we have a change in control or in the event of a highly leveraged transaction (whether or not such transaction results in a change in control) which could adversely affect holders of debt securities.

Consolidation, Merger and Sale of Assets

We may not consolidate with or merge with or into, or convey, transfer or lease all or substantially all of our properties and assets to any person (a “successor person”) unless:

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we are the surviving entity or the successor person (if other than AN2 Therapeutics) is a corporation, partnership, trust or other entity organized and validly existing under the laws of any U.S. domestic jurisdiction and expressly assumes our obligations on the debt securities and under the indenture; and

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immediately after giving effect to the transaction, no Default or Event of Default, shall have occurred and be continuing.

Notwithstanding the above, any of our subsidiaries may consolidate with, merge into or transfer all or part of its properties to us. (Section 5.1)

Events of Default

“Event of Default” means with respect to any series of debt securities, any of the following:

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default in the payment of any interest upon any debt security of that series when it becomes due and payable, and continuance of such default for a period of 30 days (unless the entire amount of the payment is deposited by us with the trustee or with a paying agent prior to the expiration of the 30-day period);

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default in the payment of principal of any security of that series at its maturity;

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default in the performance or breach of any other covenant or warranty by us in the indenture (other than a covenant or warranty that has been included in the indenture solely for the benefit of a series of debt securities other than that series), which default continues uncured for a period of 60 days after we receive written notice from the trustee or AN2 Therapeutics and the trustee receive written notice from the holders of not less than 25% in principal amount of the outstanding debt securities of that series as provided in the indenture;

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certain voluntary or involuntary events of bankruptcy, insolvency or reorganization of AN2 Therapeutics;

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any other Event of Default provided with respect to debt securities of that series that is described in the applicable prospectus supplement. (Section 6.1)

No Event of Default with respect to a particular series of debt securities (except as to certain events of bankruptcy, insolvency or reorganization) necessarily constitutes an Event of Default with respect to any other series of debt securities. (Section 6.1) The occurrence of certain Events of Default or an acceleration under the indenture may constitute an event of default under certain indebtedness of ours or our subsidiaries outstanding from time to time.

We will provide the trustee written notice of any Default or Event of Default within 30 days of becoming aware of the occurrence of such Default or Event of Default, which notice will describe in reasonable detail the status of such Default or Event of Default and what action we are taking or propose to take in respect thereof. (Section 6.1)

If an Event of Default with respect to debt securities of any series at the time outstanding occurs and is continuing, then the trustee or the holders of not less than 25% in principal amount of the outstanding debt securities of that series may, by a notice in writing to us (and to the trustee if given by the holders), declare to be due and payable immediately the principal of (or, if the debt securities of that series are discount securities, that portion of the principal amount as may be specified in the terms of that series) and accrued and unpaid interest, if any, on all debt securities of that series. In the case of an Event of Default resulting from certain events of

bankruptcy, insolvency or reorganization, the principal (or such specified amount) of and accrued and unpaid interest, if any, on all outstanding debt securities will become and be immediately due and payable without any declaration or other act on the part of the trustee or any holder of outstanding debt securities. At any time after a declaration of acceleration with respect to debt securities of any series has been made, but before a judgment or decree for payment of the money due has been obtained by the trustee, the holders of a majority in principal amount of the outstanding debt securities of that series may rescind and annul the acceleration if all Events of Default, other than the non-payment of accelerated principal and interest, if any, with respect to debt securities of that series, have been cured or waived as provided in the indenture. (Section 6.2) We refer you to the prospectus supplement relating to any series of debt securities that are discount securities for the particular provisions relating to acceleration of a portion of the principal amount of such discount securities upon the occurrence of an Event of Default.

The indenture provides that the trustee may refuse to perform any duty or exercise any of its rights or powers under the indenture unless the trustee receives indemnity satisfactory to it against any cost, liability or expense which might be incurred by it in performing such duty or exercising such right or power. (Section 7.1(e)) Subject to certain rights of the trustee, the holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee or exercising any trust or power conferred on the trustee with respect to the debt securities of that series. (Section 6.12)

No holder of any debt security of any series will have any right to institute any proceeding, judicial or otherwise, with respect to the indenture or for the appointment of a receiver or trustee, or for any remedy under the indenture, unless:

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that holder has previously given to the trustee written notice of a continuing Event of Default with respect to debt securities of that series; and

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the holders of not less than 25% in principal amount of the outstanding debt securities of that series have made written request, and offered indemnity or security satisfactory to the trustee, to the trustee to institute the proceeding as trustee, and the trustee has not received from the holders of not less than a majority in principal amount of the outstanding debt securities of that series a direction inconsistent with that request and has failed to institute the proceeding within 60 days. (Section 6.7)

Notwithstanding any other provision in the indenture, the holder of any debt security will have an absolute and unconditional right to receive payment of the principal of, premium and any interest on that debt security on or after the due dates expressed in that debt security and to institute suit for the enforcement of payment. (Section 6.8)

The indenture requires us, within 120 days after the end of our fiscal year, to furnish to the trustee a statement as to compliance with the indenture. (Section 4.3) If a Default or Event of Default occurs and is continuing with respect to the securities of any series and if it is known to a responsible officer of the trustee, the trustee shall mail to each Securityholder of the securities of that series notice of a Default or Event of Default within 90 days after it occurs or, if later, after a responsible officer of the trustee has knowledge of such Default or Event of Default. The indenture provides that the trustee may withhold notice to the holders of debt securities of any series of any Default or Event of Default (except in payment on any debt securities of that series) with respect to debt securities of that series if the trustee determines in good faith that withholding notice is in the interest of the holders of those debt securities. (Section 7.5)

Modification and Waiver

We and the trustee may modify, amend or supplement the indenture or the debt securities of any series without the consent of any holder of any debt security:

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to cure any ambiguity, defect or inconsistency;

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to comply with covenants in the indenture described above under the heading “Consolidation, Merger and Sale of Assets”;

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to provide for uncertificated securities in addition to or in place of certificated securities;

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to add guarantees with respect to debt securities of any series or secure debt securities of any series;

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to surrender any of our rights or powers under the indenture;

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to add covenants or events of default for the benefit of the holders of debt securities of any series;

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to comply with the applicable procedures of the applicable depositary;

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to make any change that does not adversely affect the rights of any holder of debt securities;

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to provide for the issuance of and establish the form and terms and conditions of debt securities of any series as permitted by the indenture;

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to effect the appointment of a successor trustee with respect to the debt securities of any series and to add to or change any of the provisions of the indenture to provide for or facilitate administration by more than one trustee; or

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to comply with requirements of the SEC in order to effect or maintain the qualification of the indenture under the Trust Indenture Act. (Section 9.1)

We may also modify and amend the indenture with the consent of the holders of at least a majority in principal amount of the outstanding debt securities of each series affected by the modifications or amendments. We may not make any modification or amendment without the consent of the holders of each affected debt security then outstanding if that amendment will:

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reduce the amount of debt securities whose holders must consent to an amendment, supplement or waiver;

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reduce the rate of or extend the time for payment of interest (including default interest) on any debt security;

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reduce the principal of or premium on or change the fixed maturity of any debt security or reduce the amount of, or postpone the date fixed for, the payment of any sinking fund or analogous obligation with respect to any series of debt securities;

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reduce the principal amount of discount securities payable upon acceleration of maturity;

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waive a default in the payment of the principal of, premium or interest on any debt security (except a rescission of acceleration of the debt securities of any series by the holders of at least a majority in aggregate principal amount of the then outstanding debt securities of that series and a waiver of the payment default that resulted from such acceleration);

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make the principal of or premium or interest on any debt security payable in currency other than that stated in the debt security;

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make any change to certain provisions of the indenture relating to, among other things, the right of holders of debt securities to receive payment of the principal of, premium and interest on those debt securities and to institute suit for the enforcement of any such payment and to waivers or amendments; or

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waive a redemption payment with respect to any debt security. (Section 9.3)

Except for certain specified provisions, the holders of at least a majority in principal amount of the outstanding debt securities of any series may on behalf of the holders of all debt securities of that series waive our compliance with provisions of the indenture. (Section 9.2) The holders of a majority in principal amount of

the outstanding debt securities of any series may on behalf of the holders of all the debt securities of such series waive any past default under the indenture with respect to that series and its consequences, except a default in the payment of the principal of, premium or any interest on any debt security of that series; provided, however, that the holders of a majority in principal amount of the outstanding debt securities of any series may rescind an acceleration and its consequences, including any related payment default that resulted from the acceleration. (Section 6.13)

Defeasance of Debt Securities and Certain Covenants in Certain Circumstances

Legal Defeasance. The indenture provides that, unless otherwise provided by the terms of the applicable series of debt securities, we may be discharged from any and all obligations in respect of the debt securities of any series (subject to certain exceptions). We will be so discharged upon the irrevocable deposit with the trustee, in trust, of money and/or U.S. government obligations or, in the case of debt securities denominated in a single currency other than U.S. Dollars, government obligations of the government that issued or caused to be issued such currency, that, through the payment of interest and principal in accordance with their terms, will provide money or U.S. government obligations in an amount sufficient in the opinion of a nationally recognized firm of independent public accountants or investment bank to pay and discharge each installment of principal, premium and interest on and any mandatory sinking fund payments in respect of the debt securities of that series on the stated maturity of those payments in accordance with the terms of the indenture and those debt securities.

This discharge may occur only if, among other things, we have delivered to the trustee an opinion of counsel stating that we have received from, or there has been published by, the United States Internal Revenue Service a ruling or, since the date of execution of the indenture, there has been a change in the applicable United States federal income tax law, in either case to the effect that, and based thereon such opinion shall confirm that, the holders of the debt securities of that series will not recognize income, gain or loss for United States federal income tax purposes as a result of the deposit, defeasance and discharge and will be subject to United States federal income tax on the same amounts and in the same manner and at the same times as would have been the case if the deposit, defeasance and discharge had not occurred. (Section 8.3)

Defeasance of Certain Covenants. The indenture provides that, unless otherwise provided by the terms of the applicable series of debt securities, upon compliance with certain conditions:

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we may omit to comply with the covenant described under the heading “Consolidation, Merger and Sale of Assets” and certain other covenants set forth in the indenture, as well as any additional covenants which may be set forth in the applicable prospectus supplement; and

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any omission to comply with those covenants will not constitute a Default or an Event of Default with respect to the debt securities of that series (“covenant defeasance”).

The conditions include:

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depositing with the trustee money and/or U.S. government obligations or, in the case of debt securities denominated in a single currency other than U.S. Dollars, government obligations of the government that issued or caused to be issued such currency, that, through the payment of interest and principal in accordance with their terms, will provide money in an amount sufficient in the opinion of a nationally recognized firm of independent public accountants or investment bank to pay and discharge each installment of principal of, premium and interest on and any mandatory sinking fund payments in respect of the debt securities of that series on the stated maturity of those payments in accordance with the terms of the indenture and those debt securities; and

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delivering to the trustee an opinion of counsel to the effect that the holders of the debt securities of that series will not recognize income, gain or loss for United States federal income tax purposes as a result of the deposit and related covenant defeasance and will be subject to United States federal income tax on the same amounts and in the same manner and at the same times as would have been the case if the deposit and related covenant defeasance had not occurred. (Section 8.4)

No Personal Liability of Directors, Officers, Employees or Securityholders

None of our past, present or future directors, officers, employees or securityholders, as such, will have any liability for any of our obligations under the debt securities or the indenture or for any claim based on, or in respect or by reason of, such obligations or their creation. By accepting a debt security, each holder waives and releases all such liability. This waiver and release is part of the consideration for the issue of the debt securities. However, this waiver and release may not be effective to waive liabilities under U.S. federal securities laws, and it is the view of the SEC that such a waiver is against public policy.

Governing Law

The indenture and the debt securities, including any claim or controversy arising out of or relating to the indenture or the securities, will be governed by the laws of the State of New York.

The indenture will provide that we, the trustee and the holders of the debt securities (by their acceptance of the debt securities) irrevocably waive, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to the indenture, the debt securities or the transactions contemplated thereby.

The indenture will provide that any legal suit, action or proceeding arising out of or based upon the indenture or the transactions contemplated thereby may be instituted in the federal courts of the United States of America located in the City of New York or the courts of the State of New York in each case located in the City of New York, and we, the trustee and the holder of the debt securities (by their acceptance of the debt securities) irrevocably submit to the non-exclusive jurisdiction of such courts in any such suit, action or proceeding. The indenture will further provide that service of any process, summons, notice or document by mail (to the extent allowed under any applicable statute or rule of court) to such party’s address set forth in the indenture will be effective service of process for any suit, action or other proceeding brought in any such court. The indenture will further provide that we, the trustee and the holders of the debt securities (by their acceptance of the debt securities) irrevocably and unconditionally waive any objection to the laying of venue of any suit, action or other proceeding in the courts specified above and irrevocably and unconditionally waive and agree not to plead or claim any such suit, action or other proceeding has been brought in an inconvenient forum. (Section 10.10)

DESCRIPTION OF WARRANTS

We may issue warrants for the purchase of shares of our common stock or preferred stock or of debt securities. We may issue warrants independently or together with other securities, and the warrants may be attached to or separate from any offered securities. Each series of warrants will be issued under a separate warrant agreement to be entered into between us and the investors or a warrant agent. The following summary of material provisions of the warrants and warrant agreements are subject to, and qualified in their entirety by reference to, all the provisions of the warrant agreement and warrant certificate applicable to a particular series of warrants. The terms of any warrants offered under a prospectus supplement may differ from the terms described below. We urge you to read the applicable prospectus supplement and any related free writing prospectus, as well as the complete warrant agreements and warrant certificates that contain the terms of the warrants.

The particular terms of any issue of warrants will be described in the prospectus supplement relating to the issue. Those terms may include:

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the number of shares of common stock or preferred stock purchasable upon the exercise of warrants to purchase such shares and the price at which such number of shares may be purchased upon such exercise;

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the designation, stated value and terms (including, without limitation, liquidation, dividend, conversion and voting rights) of the series of preferred stock purchasable upon exercise of warrants to purchase preferred stock;

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the principal amount of debt securities that may be purchased upon exercise of a debt warrant and the exercise price for the warrants, which may be payable in cash, securities or other property;

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the date, if any, on and after which the warrants and the related debt securities, preferred stock or common stock will be separately transferable;

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the terms of any rights to redeem or call the warrants;

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the date on which the right to exercise the warrants will commence and the date on which the right will expire;

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United States Federal income tax consequences applicable to the warrants; and

•

any additional terms of the warrants, including terms, procedures, and limitations relating to the exchange, exercise and settlement of the warrants.

Holders of equity warrants will not be entitled:

•

to vote, consent or receive dividends;

•

receive notice as shareholders with respect to any meeting of shareholders for the election of our directors or any other matter; or

•

exercise any rights as shareholders of AN2 Therapeutics.

Each warrant will entitle its holder to purchase the principal amount of debt securities or the number of shares of preferred stock or common stock at the exercise price set forth in, or calculable as set forth in, the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

A holder of warrant certificates may exchange them for new warrant certificates of different denominations, present them for registration of transfer and exercise them at the corporate trust office of the warrant agent or any

other office indicated in the applicable prospectus supplement. Until any warrants to purchase debt securities are exercised, the holder of the warrants will not have any rights of holders of the debt securities that can be purchased upon exercise, including any rights to receive payments of principal, premium or interest on the underlying debt securities or to enforce covenants in the applicable indenture. Until any warrants to purchase common stock or preferred stock are exercised, the holders of the warrants will not have any rights of holders of the underlying common stock or preferred stock, including any rights to receive dividends or payments upon any liquidation, dissolution or winding up on the common stock or preferred stock, if any.

DESCRIPTION OF UNITS

We may issue units consisting of any combination of the other types of securities offered under this prospectus in one or more series. We may evidence each series of units by unit certificates that we will issue under a separate agreement. We may enter into unit agreements with a unit agent. Each unit agent will be a bank or trust company that we select. We will indicate the name and address of the unit agent in the applicable prospectus supplement relating to a particular series of units.

The following description, together with the additional information included in any applicable prospectus supplement, summarizes the general features of the units that we may offer under this prospectus. You should read any prospectus supplement and any free writing prospectus that we may authorize to be provided to you related to the series of units being offered, as well as the complete unit agreements that contain the terms of the units. Specific unit agreements will contain additional important terms and provisions and we will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from another report that we file with the SEC, the form of each unit agreement relating to units offered under this prospectus.

If we offer any units, certain terms of that series of units will be described in the applicable prospectus supplement, including, without limitation, the following, as applicable:

•

the title of the series of units;

•

identification and description of the separate constituent securities comprising the units;

•

the price or prices at which the units will be issued;

•

the date, if any, on and after which the constituent securities comprising the units will be separately transferable;

•

a discussion of certain United States federal income tax considerations applicable to the units; and

•

any other terms of the units and their constituent securities.

GLOBAL SECURITIES

Book-Entry, Delivery and Form

Unless we indicate differently in any applicable prospectus supplement or free writing prospectus, the securities initially will be issued in book-entry form and represented by one or more global notes or global securities, or, collectively, global securities. The global securities will be deposited with, or on behalf of, The Depository Trust Company, New York, New York, as depositary (“DTC”), and registered in the name of Cede & Co., the nominee of DTC. Unless and until it is exchanged for individual certificates evidencing securities under the limited circumstances described below, a global security may not be transferred except as a whole by the depositary to its nominee or by the nominee to the depositary, or by the depositary or its nominee to a successor depositary or to a nominee of the successor depositary.

DTC has advised us that it is:

•

a limited-purpose trust company organized under the New York Banking Law;

•

a “banking organization” within the meaning of the New York Banking Law;

•

a member of the Federal Reserve System;

•

a “clearing corporation” within the meaning of the New York Uniform Commercial Code; and

•

a “clearing agency” registered pursuant to the provisions of Section 17A of the Exchange Act.

DTC holds securities that its participants deposit with DTC. DTC also facilitates the settlement among its participants of securities transactions, such as transfers and pledges, in deposited securities through electronic computerized book-entry changes in participants’ accounts, thereby eliminating the need for physical movement of securities certificates. “Direct participants” in DTC include securities brokers and dealers, including underwriters, banks, trust companies, clearing corporations and other organizations. DTC is a wholly-owned subsidiary of The Depository Trust & Clearing Corporation (“DTCC”). DTCC is the holding company for DTC, National Securities Clearing Corporation and Fixed Income Clearing Corporation, all of which are registered clearing agencies. DTCC is owned by the users of its regulated subsidiaries. Access to the DTC system is also available to others, which we sometimes refer to as indirect participants, that clear through or maintain a custodial relationship with a direct participant, either directly or indirectly. The rules applicable to DTC and its participants are on file with the SEC.

Purchases of securities under the DTC system must be made by or through direct participants, which will receive a credit for the securities on DTC’s records. The ownership interest of the actual purchaser of a security, which we sometimes refer to as a beneficial owner, is in turn recorded on the direct and indirect participants’ records. Beneficial owners of securities will not receive written confirmation from DTC of their purchases. However, beneficial owners are expected to receive written confirmations providing details of their transactions, as well as periodic statements of their holdings, from the direct or indirect participants through which they purchased securities. Transfers of ownership interests in global securities are to be accomplished by entries made on the books of participants acting on behalf of beneficial owners. Beneficial owners will not receive certificates representing their ownership interests in the global securities, except under the limited circumstances described below.

To facilitate subsequent transfers, all global securities deposited by direct participants with DTC will be registered in the name of DTC’s partnership nominee, Cede & Co., or such other name as may be requested by an authorized representative of DTC. The deposit of securities with DTC and their registration in the name of Cede & Co. or such other nominee will not change the beneficial ownership of the securities. DTC has no knowledge of the actual beneficial owners of the securities. DTC’s records reflect only the identity of the direct participants to whose accounts the securities are credited, which may or may not be the beneficial owners. The participants are responsible for keeping account of their holdings on behalf of their customers.

So long as the securities are in book-entry form, you will receive payments and may transfer securities only through the facilities of the depositary and its direct and indirect participants. We will maintain an office or agency in the location specified in the prospectus supplement for the applicable securities, where notices and demands in respect of the securities and the indenture may be delivered to us and where certificated securities may be surrendered for payment, registration of transfer or exchange.

Conveyance of notices and other communications by DTC to direct participants, by direct participants to indirect participants and by direct participants and indirect participants to beneficial owners will be governed by arrangements among them, subject to any legal requirements in effect from time to time.

Redemption notices will be sent to DTC. If less than all of the securities of a particular series are being redeemed, DTC’s practice is to determine by lot the amount of the interest of each direct participant in the securities of such series to be redeemed.

Neither DTC nor Cede & Co. (or such other DTC nominee) will consent or vote with respect to the securities. Under its usual procedures, DTC will mail an omnibus proxy to us as soon as possible after the record date. The omnibus proxy assigns the consenting or voting rights of Cede & Co. to those direct participants to whose accounts the securities of such series are credited on the record date, identified in a listing attached to the omnibus proxy.

So long as securities are in book-entry form, we will make payments on those securities to the depositary or its nominee, as the registered owner of such securities, by wire transfer of immediately available funds. If securities are issued in definitive certificated form under the limited circumstances described below and unless if otherwise provided in the description of the applicable securities herein or in the applicable prospectus supplement, we will have the option of making payments by check mailed to the addresses of the persons entitled to payment or by wire transfer to bank accounts in the United States designated in writing to the applicable trustee or other designated party at least 15 days before the applicable payment date by the persons entitled to payment, unless a shorter period is satisfactory to the applicable trustee or other designated party.

Redemption proceeds, distributions and dividend payments on the securities will be made to Cede & Co., or such other nominee as may be requested by an authorized representative of DTC. DTC’s practice is to credit direct participants’ accounts upon DTC’s receipt of funds and corresponding detail information from us on the payment date in accordance with their respective holdings shown on DTC records. Payments by participants to beneficial owners will be governed by standing instructions and customary practices, as is the case with securities held for the account of customers in bearer form or registered in “street name.” Those payments will be the responsibility of participants and not of DTC or us, subject to any statutory or regulatory requirements in effect from time to time. Payment of redemption proceeds, distributions and dividend payments to Cede & Co., or such other nominee as may be requested by an authorized representative of DTC, is our responsibility, disbursement of payments to direct participants is the responsibility of DTC, and disbursement of payments to the beneficial owners is the responsibility of direct and indirect participants.

Except under the limited circumstances described below, purchasers of securities will not be entitled to have securities registered in their names and will not receive physical delivery of securities. Accordingly, each beneficial owner must rely on the procedures of DTC and its participants to exercise any rights under the securities and the indenture.

The laws of some jurisdictions may require that some purchasers of securities take physical delivery of securities in definitive form. Those laws may impair the ability to transfer or pledge beneficial interests in securities.

DTC may discontinue providing its services as securities depositary with respect to the securities at any time by giving reasonable notice to us. Under such circumstances, in the event that a successor depositary is not obtained, securities certificates are required to be printed and delivered.

As noted above, beneficial owners of a particular series of securities generally will not receive certificates representing their ownership interests in those securities. However, if:

•

DTC notifies us that it is unwilling or unable to continue as a depositary for the global security or securities representing such series of securities or if DTC ceases to be a clearing agency registered under the Exchange Act at a time when it is required to be registered and a successor depositary is not appointed within 90 days of the notification to us or of our becoming aware of DTC’s ceasing to be so registered, as the case may be;

•

we determine, in our sole discretion, not to have such securities represented by one or more global securities; or

•

an Event of Default has occurred and is continuing with respect to such series of securities,

we will prepare and deliver certificates for such securities in exchange for beneficial interests in the global securities. Any beneficial interest in a global security that is exchangeable under the circumstances described in the preceding sentence will be exchangeable for securities in definitive certificated form registered in the names that the depositary directs. It is expected that these directions will be based upon directions received by the depositary from its participants with respect to ownership of beneficial interests in the global securities.

Euroclear and Clearstream

If so provided in the applicable prospectus supplement, you may hold interests in a global security through Clearstream Banking S.A. (“Clearstream”) or Euroclear Bank S.A./N.V., as operator of the Euroclear System (“Euroclear”) either directly if you are a participant in Clearstream or Euroclear or indirectly through organizations which are participants in Clearstream or Euroclear. Clearstream and Euroclear will hold interests on behalf of their respective participants through customers’ securities accounts in the names of Clearstream and Euroclear, respectively, on the books of their respective U.S. depositaries, which in turn will hold such interests in customers’ securities accounts in such depositaries’ names on DTC’s books.

Clearstream and Euroclear are securities clearance systems in Europe. Clearstream and Euroclear hold securities for their respective participating organizations and facilitate the clearance and settlement of securities transactions between those participants through electronic book-entry changes in their accounts, thereby eliminating the need for physical movement of certificates.

Payments, deliveries, transfers, exchanges, notices and other matters relating to beneficial interests in global securities owned through Euroclear or Clearstream must comply with the rules and procedures of those systems. Transactions between participants in Euroclear or Clearstream, on one hand, and other participants in DTC, on the other hand, are also subject to DTC’s rules and procedures.

Investors will be able to make and receive through Euroclear and Clearstream payments, deliveries, transfers and other transactions involving any beneficial interests in global securities held through those systems only on days when those systems are open for business. Those systems may not be open for business on days when banks, brokers and other institutions are open for business in the United States.

Cross-market transfers between participants in DTC, on the one hand, and participants in Euroclear or Clearstream, on the other hand, will be effected through DTC in accordance with the DTC’s rules on behalf of Euroclear or Clearstream, as the case may be, by their respective U.S. depositaries; however, such cross-market transactions will require delivery of instructions to Euroclear or Clearstream, as the case may be, by the counterparty in such system in accordance with the rules and procedures and within the established deadlines (European time) of such system. Euroclear or Clearstream, as the case may be, will, if the transaction meets its settlement requirements, deliver instructions to its U.S. depositary to take action to effect final settlement on its behalf by delivering or receiving interests in the global securities through DTC, and making or receiving payment in accordance with normal procedures for same-day fund settlement. Participants in Euroclear or Clearstream may not deliver instructions directly to their respective U.S. depositaries.

Due to time zone differences, the securities accounts of a participant in Euroclear or Clearstream purchasing an interest in a global security from a direct participant in DTC will be credited, and any such crediting will be reported to the relevant participant in Euroclear or Clearstream, during the securities settlement processing day (which must be a business day for Euroclear or Clearstream) immediately following the settlement date of DTC. Cash received in Euroclear or Clearstream as a result of sales of interests in a global security by or through a participant in Euroclear or Clearstream to a direct participant in DTC will be received with value on the settlement date of DTC but will be available in the relevant Euroclear or Clearstream cash account only as of the business day for Euroclear or Clearstream following DTC’s settlement date.

Other

The information in this section of this prospectus concerning DTC, Clearstream, Euroclear and their respective book-entry systems has been obtained from sources that we believe to be reliable, but we do not take responsibility for this information. This information has been provided solely as a matter of convenience. The rules and procedures of DTC, Clearstream and Euroclear are solely within the control of those organizations and could change at any time. Neither we nor the trustee nor any agent of ours or of the trustee has any control over those entities and none of us takes any responsibility for their activities. You are urged to contact DTC, Clearstream and Euroclear or their respective participants directly to discuss those matters. In addition, although we expect that DTC, Clearstream and Euroclear will perform the foregoing procedures, none of them is under any obligation to perform or continue to perform such procedures and such procedures may be discontinued at any time. Neither we nor any agent of ours will have any responsibility for the performance or nonperformance by DTC, Clearstream and Euroclear or their respective participants of these or any other rules or procedures governing their respective operations.

SELLING SECURITYHOLDERS

This prospectus also relates to the possible resale by certain of our securityholders, who we refer to in this prospectus as the “selling securityholders,” of up to an aggregate of 14,035,104 shares of our common stock, consisting of 8,245,611 shares of our common stock that were issued and outstanding, and 5,789,493 shares of our common stock that are issuable upon exercise of certain pre-funded warrants that were issued and outstanding, prior to the original date of filing of the registration statement of which this prospectus forms a part. The selling securityholders originally acquired these shares of our common stock and pre-funded warrants in a private placement pursuant to a securities purchase agreement, dated March 8, 2026, by and among the Company and the investors listed therein.

Information about the selling securityholders, where applicable, including their identities, the amount of shares of common stock owned by each selling securityholder prior to the offering, the number of shares of our common stock to be offered by each selling securityholder and the amount of common stock to be owned by each selling securityholder after completion of the offering, will be set forth in an applicable prospectus supplement, documents incorporated by reference or in a free writing prospectus we file with the SEC. The applicable prospectus supplement will also disclose whether any of the selling securityholders has held any position or office with, has been employed by or otherwise has had a material relationship with us during the three years prior to the date of the prospectus supplement.

The selling securityholders may not sell any shares of our common stock pursuant to this prospectus until we have identified such selling securityholders and the shares being offered for resale by such selling securityholders in a subsequent prospectus supplement. However, the selling securityholders may sell or transfer all or a portion of their shares of our common stock pursuant to any available exemption from the registration requirements of the Securities Act.

PLAN OF DISTRIBUTION

We or the selling securityholders may sell the securities from time to time pursuant to underwritten public offerings, negotiated transactions, block trades or a combination of these methods or through underwriters or dealers, through agents and/or directly to one or more purchasers. The securities may be distributed from time to time in one or more transactions:

•

at a fixed price or prices, which may be changed;

•

at market prices prevailing at the time of sale;

•

at prices related to such prevailing market prices; or

•

at negotiated prices.

Each time that we or any of the selling securityholders sell securities covered by this prospectus, we or the selling securityholders will provide a prospectus supplement or supplements that will describe the method of distribution and set forth the terms and conditions of the offering of such securities, including the offering price of the securities and the proceeds to us or the selling securityholders, if applicable.

Offers to purchase the securities being offered by this prospectus may be solicited directly. Agents may also be designated to solicit offers to purchase the securities from time to time. Any agent involved in the offer or sale of our securities will be identified in a prospectus supplement.

If a dealer is utilized in the sale of the securities being offered by this prospectus, the securities will be sold to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of resale.

If an underwriter is utilized in the sale of the securities being offered by this prospectus, an underwriting agreement will be executed with the underwriter at the time of sale and the name of any underwriter will be provided in the prospectus supplement that the underwriter will use to make resales of the securities to the public. In connection with the sale of the securities, we, or the selling securityholders, or the purchasers of securities for whom the underwriter may act as agent, may compensate the underwriter in the form of underwriting discounts or commissions. The underwriter may sell the securities to or through dealers, and those dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters and/or commissions from the purchasers for which they may act as agent. Unless otherwise indicated in a prospectus supplement, an agent will be acting on a best efforts basis and a dealer will purchase securities as a principal, and may then resell the securities at varying prices to be determined by the dealer.

Any compensation paid to underwriters, dealers or agents in connection with the offering of the securities, and any discounts, concessions or commissions allowed by underwriters to participating dealers will be provided in the applicable prospectus supplement. Underwriters, dealers and agents participating in the distribution of the securities may be deemed to be underwriters within the meaning of the Securities Act of 1933, as amended, and any discounts and commissions received by them and any profit realized by them on resale of the securities may be deemed to be underwriting discounts and commissions. We may enter into agreements to indemnify underwriters, dealers and agents against civil liabilities, including liabilities under the Securities Act, or to contribute to payments they may be required to make in respect thereof and to reimburse those persons for certain expenses.

Any common stock will be listed on the Nasdaq Global Select Market, but any other securities may or may not be listed on a national securities exchange. To facilitate the offering of securities, certain persons participating in the offering may engage in transactions that stabilize, maintain or otherwise affect the price of the securities. This may include over-allotments or short sales of the securities, which involve the sale by persons participating in the offering of more securities than were sold to them. In these circumstances, these persons

would cover such over-allotments or short positions by making purchases in the open market or by exercising their over-allotment option, if any. In addition, these persons may stabilize or maintain the price of the securities by bidding for or purchasing securities in the open market or by imposing penalty bids, whereby selling concessions allowed to dealers participating in the offering may be reclaimed if securities sold by them are repurchased in connection with stabilization transactions. The effect of these transactions may be to stabilize or maintain the market price of the securities at a level above that which might otherwise prevail in the open market. These transactions may be discontinued at any time.

We may engage in at the market offerings into an existing trading market in accordance with Rule 415(a)(4) under the Securities Act. In addition, we may enter into derivative transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement so indicates, in connection with those derivatives, the third parties may sell securities covered by this prospectus and the applicable prospectus supplement, including in short sale transactions. If so, the third party may use securities pledged by us or borrowed from us or others to settle those sales or to close out any related open borrowings of stock, and may use securities received from us in settlement of those derivatives to close out any related open borrowings of stock. The third party in such sale transactions will be an underwriter and, if not identified in this prospectus, will be named in the applicable prospectus supplement (or a post-effective amendment). In addition, we may otherwise loan or pledge securities to a financial institution or other third party that in turn may sell the securities short using this prospectus and an applicable prospectus supplement. Such financial institution or other third party may transfer its economic short position to investors in our securities or in connection with a concurrent offering of other securities.

The specific terms of any lock-up provisions in respect of any given offering will be described in the applicable prospectus supplement.

The underwriters, dealers and agents may engage in transactions with us, or perform services for us, in the ordinary course of business for which they receive compensation.

LEGAL MATTERS

Latham & Watkins LLP will pass upon certain legal matters relating to the issuance and sale of the securities offered hereby on behalf of AN2 Therapeutics, Inc. Additional legal matters may be passed upon for us, the selling securityholders or any underwriters, dealers or agents, by counsel that we will name in the applicable prospectus supplement.

EXPERTS

The financial statements incorporated in this Prospectus by reference to the Annual Report on Form 10-K for the year ended December 31, 2025 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

The information in this preliminary prospectus supplement is not complete and may be changed. These securities may not be sold until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus supplement is not an offer to sell nor does it seek an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

Subject to Completion, dated April 9, 2026

PROSPECTUS SUPPLEMENT

$80,000,000

LOGO

Common Stock

We have entered into an open market sale agreement (the “sales agreement”) with Jefferies LLC (“Jefferies”), dated April 9, 2026, relating to shares of our common stock. In accordance with the terms of the sales agreement, we may offer and sell shares of our common stock having an aggregate offering price of up to $80,000,000 from time to time through Jefferies acting as sales agent or principal. This prospectus supplement relates to $80,000,000 of shares of our common stock that we may sell pursuant to the sales agreement.

Our common stock is listed on the Nasdaq Global Select Market under the symbol “ANTX.” On April 8, 2026, the last reported sale price of our common stock was $3.34 per share.

Sales of our common stock, if any, under this prospectus supplement may be made in sales deemed to be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended (the “Securities Act”). Jefferies is not required to sell any specific number or dollar amounts of securities but will act as a sales agent using commercially reasonable efforts consistent with its normal trading and sales practices, on mutually agreed terms between Jefferies and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

The compensation to Jefferies for sales of common stock sold pursuant to the sales agreement will be an amount up to 3.0% of the gross proceeds of any shares of common stock sold under the sales agreement. In connection with the sale of the common stock on our behalf, Jefferies will be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation to Jefferies will be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contribution to Jefferies with respect to certain liabilities, including liabilities under the Securities Act or the Securities Exchange Act of 1934, as amended.

Our business and an investment in our common stock involve significant risks. These risks are described under the caption “Risk Factors” beginning on page S-6 of this prospectus supplement and in the documents incorporated by reference into this prospectus supplement.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus supplement. Any representation to the contrary is a criminal offense.

Jefferies

, 2026.

TABLE OF CONTENTS


ABOUT THIS PROSPECTUS SUPPLEMENT			S-1
PROSPECTUS SUPPLEMENT SUMMARY			S-3
THE OFFERING			S-5
RISK FACTORS			S-6
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS			S-9
USE OF PROCEEDS			S-11
DILUTION			S-12
PLAN OF DISTRIBUTION			S-14
LEGAL MATTERS			S-15
EXPERTS			S-15
WHERE YOU CAN FIND MORE INFORMATION			S-16
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE			S-17

ABOUT THIS PROSPECTUS SUPPLEMENT

This prospectus supplement is part of a registration statement on Form S-3 that we have filed with the Securities and Exchange Commission, or SEC, utilizing a “shelf” registration process. Under the shelf registration statement process we may offer shares of our common stock, preferred stock, debt securities, warrants and units, including common stock or preferred stock upon conversion of debt securities, common stock upon conversion of preferred stock, or common stock, preferred stock or debt securities upon the exercise of warrants, having an aggregate offering price of up to $300,000,000. Under this prospectus supplement, we may offer shares of our common stock having an aggregate offering price of up to $80,000,000 from time to time at prices and on terms to be determined by market conditions at the time of offering. The $80,000,000 of common stock that may be offered, issued and sold under this prospectus supplement is included in the $300,000,000 of securities that may be offered, issued and sold by us pursuant to our shelf registration statement.

We provide information to you about this offering of shares of our common stock in this prospectus supplement, which describes the specific details regarding this offering. If information in this prospectus supplement is inconsistent with the information in the accompanying prospectus or the documents incorporated by reference in this prospectus supplement filed prior to the date of this prospectus supplement, you should rely on this prospectus supplement. However, if any statement in one of these documents is inconsistent with a statement in another document having a later date—for example, a document incorporated by reference in this prospectus supplement—the statement in the document having the later date modifies or supersedes the earlier statement as our business, financial condition, results of operations and prospects may have changed since the earlier dates.

We have not, and Jefferies has not, authorized any other person to provide you with any information other than that contained in or incorporated by reference in this prospectus supplement, the accompanying prospectus or any free writing prospectus prepared by or on behalf of us or to which we have referred you. Neither we nor Jefferies take responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We are not, and Jefferies is not, making an offer to sell or soliciting an offer to buy our securities in any jurisdiction in which an offer or solicitation is not authorized or in which the person making that offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make an offer or solicitation. You should assume that the information appearing in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein and therein, and in any free writing prospectus that we may authorize for use in connection with this offering, is accurate only as of the date of those respective documents. Our business, financial condition, results of operations and prospects may have changed since those dates. You should read this prospectus supplement, the accompanying prospectus, the documents incorporated by reference herein and therein as described under the headings “Where You Can Find More Information” and “Incorporation of Certain Information by Reference,” and any free writing prospectus that we may authorize for use in connection with this offering, in their entirety before making an investment decision. These documents contain important information that you should consider when making your investment decision.

We and Jefferies are offering to sell, and seeking offers to buy, shares of common stock only in jurisdictions where offers and sales are permitted. The distribution of this prospectus supplement and the offering of our common stock in certain jurisdictions may be restricted by law. Persons outside the United States who come into possession of this prospectus supplement must inform themselves about, and observe any restrictions relating to, the offering of our common stock and the distribution of this prospectus supplement outside the United States. This prospectus supplement does not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.

S-1

addition, projections, assumptions and estimates of our future performance and the future performance of the industry in which we operate are necessarily subject to a high degree of uncertainty and risk due to a variety of factors, including those described in “Risk Factors” and elsewhere in this prospectus supplement and documents incorporated by reference into this prospectus supplement. These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties and by us.

This prospectus supplement contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus supplement and the accompanying prospectus are a part, and you may obtain copies of those documents as described below under the headings “Where You Can Find More Information” and “Incorporation of Certain Information by Reference.”

S-2

PROSPECTUS SUPPLEMENT SUMMARY

This summary highlights selected information contained elsewhere in this prospectus supplement or incorporated by reference in this prospectus supplement, and does not contain all of the information that you need to consider in making your investment decision. You should carefully read this entire prospectus supplement, the accompanying prospectus and any related free writing prospectus, including the risks of investing in our securities discussed under the heading “Risk Factors” contained in this prospectus supplement, the accompanying prospectus and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus supplement. You should also carefully read the information incorporated by reference into this prospectus supplement, including our financial statements, and the exhibits to the registration statement of which this prospectus supplement is a part.

References in this prospectus supplement to “AN2,” “AN2 Therapeutics,” “the Company,” “we,” “us” and “our” refer to AN2 Therapeutics, Inc., a Delaware corporation, unless otherwise specified.

AN2 Therapeutics, Inc.

Overview

Corporate Information

We were incorporated in February 2017 as a Delaware corporation and launched operations in November 2019. Our principal executive offices are located at 1300 El Camino Real, Suite 100, Menlo Park, California 94025 and our telephone number is (650) 331-9090. Our website address is www.an2therapeutics.com. The information contained on, or that can be accessed through, our website will not be deemed to be incorporated by reference into this prospectus supplement and does not constitute part of this prospectus supplement. Our website address is included in this prospectus supplement as an inactive textual reference only.

We use the AN2 Therapeutics logo and other marks as trademarks in the United States and other countries. This prospectus supplement contains references to our trademarks and service marks and to those belonging to other entities. Solely for convenience, trademarks and trade names referred to in this prospectus supplement, including logos, artwork, and other visual displays, may appear without the ^® or ^™ symbols, but such references are not intended to indicate in any way that the respective owners will not assert, to the fullest extent under applicable law, their rights or the rights of the applicable licensor to these trademarks and trade names. We do not intend our use or display of other entities’ trade names, trademarks, or service marks to imply a relationship with, or endorsement or sponsorship of us by, any other entity.

Implications of Being an Emerging Growth Company and a Smaller Reporting Company

We are an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). We may take advantage of certain exemptions from various public company reporting requirements, including not being required to have our internal control over financial reporting audited by our independent registered public accounting firm under Section 404 of the Sarbanes-Oxley Act of 2002 (“Sarbanes-Oxley Act”), reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements, and exemptions from the requirements of holding a nonbinding advisory vote on executive

S-3

compensation and any golden parachute payments. We may take advantage of these exemptions until we are no longer an “emerging growth company.” We will cease to be an emerging growth company on December 31, 2027, or prior to such date if certain earlier events occur, including if we become a “large accelerated filer” as defined in Rule 12b-2 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), our annual gross revenues exceed $1.235 billion or we issue more than $1.0 billion of non-convertible debt in any three-year period.

Under the JOBS Act, emerging growth companies can also delay adopting new or revised accounting standards until such time as those standards apply to private companies. We have elected to use this extended transition period under the JOBS Act until the earlier of the date we (i) are no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act.

We are also a “smaller reporting company” as defined in the Exchange Act. We may continue to be a smaller reporting company even after we are no longer an emerging growth company, which would allow us to take advantage of many of the same exemptions available to emerging growth companies, including not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act and reduced disclosure obligations regarding executive compensation. We will be able to take advantage of these scaled disclosures for so long as our voting and non-voting common stock held by non-affiliates is less than $250.0 million measured on the last business day of our second fiscal quarter, or our annual revenue is less than $100.0 million during the most recently completed fiscal year and our voting and non-voting common stock held by non-affiliates is less than $700.0 million measured on the last business day of our second fiscal quarter.

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THE OFFERING

Common stock offered by us

Shares of our common stock having an aggregate offering price of up to $80,000,000.

Common stock to be outstanding after this offering

Up to 51,365,266 shares (as more fully described in the notes following this table), assuming sales of 23,952,095 shares of our common stock in this offering at an offering price of $3.34 per share, which was the last reported sale price of our common stock on the Nasdaq Global Select Market on April 8, 2026. The actual number of shares issued will vary depending on the sales price under this offering.

Manner of offering

“At the market” offering that may be made from time to time through Jefferies as sales agent or principal. See “Plan of Distribution” on page S-14.

Use of proceeds

We currently intend to use the net proceeds from this offering, if any, primarily to fund the research and development of our product candidates and for working capital and general corporate purposes. See “Use of Proceeds” on page S-11.

Risk factors

You should read the “Risk Factors” section of this prospectus supplement and in the documents incorporated by reference into this prospectus supplement for a discussion of factors to consider before deciding to purchase shares of our common stock.

Nasdaq Global Select Market symbol

“ANTX”

The number of our shares of common stock shown above to be outstanding after this offering is based on 27,413,171 shares of common stock outstanding as of December 31, 2025, and excludes the following, all as of December 31, 2025:

•

5,466,222 shares of common stock issuable upon the exercise of outstanding stock options with a weighted-average exercise price of $6.56 per share;

•

856,160 shares of common stock issuable upon the vesting and settlement of outstanding restricted stock units;

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2,952,000 shares of common stock issuable upon the exercise of outstanding pre-funded warrants, at an exercise price of $0.00001 per share;

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783,106 shares of common stock reserved for future issuance under our 2022 Equity Incentive Plan, or 2022 Plan, as of December 31, 2025, plus any additional shares of our common stock that may become available under our 2022 Plan; and

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775,882 shares of our common stock reserved for issuance under our 2022 Employee Stock Purchase Plan, or ESPP, as of December 31, 2025, as well as any future increases in the number of shares of our common stock reserved for issuance under the ESPP.

Subsequent to December 31, 2025 and through the date of this prospectus supplement, we sold in a private placement 8,245,611 shares of our common stock at a price of $2.85 per share and pre-funded warrants to purchase up to 5,789,493 shares of our common stock at a price of $2.84999 per pre-funded warrant for aggregate gross proceeds of approximately $40 million. Each pre-funded warrant has an exercise price of $0.00001 per share of common stock, is exercisable immediately and is exercisable until exercised in full, subject to ownership limitations.

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RISK FACTORS

Investing in our common stock involves a high degree of risk. Before deciding whether to invest in our common stock, you should consider carefully the risks and uncertainties described below and discussed under the heading “Risk Factors” contained in our most recent Annual Report on Form 10-K and in our most recent Quarterly Report on Form 10-Q, as updated by our subsequent filings with the SEC, which are incorporated by reference into this prospectus supplement in their entirety, together with other information in this prospectus supplement, the documents incorporated by reference and any free writing prospectus that we may authorize for use in connection with this offering. The risks described in these documents are not the only ones we face, but those that we consider to be material. There may be other unknown or unpredictable economic, business, competitive, regulatory or other factors that could have material adverse effects on our business, financial condition, results of operations and prospects. Past financial performance may not be a reliable indicator of future performance, and historical trends should not be used to anticipate results or trends in future periods. If any of these risks actually occurs, our business, financial condition, results of operations and prospects could be seriously harmed. This could cause the trading price of our common stock to decline, resulting in a loss of all or part of your investment. Please also read carefully the section below entitled “Cautionary Note Regarding Forward-Looking Statements.”

Additional Risks Related to This Offering

Investors in this offering may pay a much higher price than the book value of our common stock and therefore you may incur immediate and substantial dilution of your investment.

The public offering price of our common stock in this offering may be substantially higher than the net tangible book value per share of common stock based on the total value of our tangible assets less our total liabilities immediately following this offering. Assuming that an aggregate of 23,952,095 shares of our common stock are sold at a price of $3.34 per share pursuant to this prospectus supplement, which was the closing price of our common stock on the Nasdaq Global Select Market on April 8, 2026, for an aggregate offering price of approximately $80,000,000 in this offering, and after deducting commissions and estimated aggregate offering expenses payable by us, you would experience immediate and substantial dilution of approximately $0.80 per share, representing the difference between our adjusted net tangible book value per share as of December 31, 2025 after giving effect to this offering and the assumed public offering price. For a further description of the dilution that you will experience immediately after this offering, see the section titled “Dilution.”

Raising additional capital may cause dilution to our stockholders, including purchasers of our common stock in this offering, restrict our operations or require us to relinquish substantial rights.

To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms of these new securities may include liquidation or other preferences that adversely affect your rights as a common stockholder. Debt financing, if available, may involve fixed payment obligations or agreements that include covenants limiting or restricting our ability to take specific actions such as incurring additional debt, making capital expenditures or declaring dividends. If we raise additional funds through partnerships, collaborations, strategic alliances or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, product candidates or future revenue streams, or grant licenses on terms that are not favorable to us. We cannot assure you that we will be able to obtain additional funding if and when necessary. If we are unable to obtain adequate financing on a timely basis, we could be required to delay, scale back or eliminate one or more of our clinical or discovery programs or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves. In addition, we may seek additional capital due to favorable market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans.

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Sales of a substantial number of shares of our common stock in the public market could cause our stock price to fall.

Sales of a substantial number of shares of our common stock in the public market could occur at any time. As of the date of this prospectus supplement, we had 35,985,599 shares of our common stock outstanding. If our stockholders sell, or the market perceives that our stockholders intend to sell, substantial amount of our common stock in the public market, the market price of our common stock could decline significantly.

Shares issued upon the exercise of stock options and the vesting and settlement of restricted stock units outstanding under our equity incentive plans or pursuant to future awards granted under those plans will become available for sale in the public market to the extent permitted by the provisions of applicable vesting schedules and Rule 144 and Rule 701 under the Securities Act.

Moreover, certain holders of our common stock have rights, subject to conditions, to require us to file registration statements covering their shares or to include their shares in registration statements that we may file for ourselves or other stockholders. Registration of these shares under the Securities Act would result in the shares becoming freely tradeable in the public market, subject to the restrictions of Rule 144 in the case of our affiliates. If any of these additional shares are sold, or if it is perceived that they will be sold, in the public market, the market price of our common stock could decline.

Management will have broad discretion as to the use of the proceeds from this offering, and may not use the proceeds effectively and its investment of these proceeds may not yield a favorable return.

Because we have not designated the amount of net proceeds from this offering to be used for any particular purpose, our management will have broad discretion as to the application of the net proceeds from this offering and could use them for purposes other than those contemplated at the time of the offering. Our management may use the net proceeds for corporate purposes that may not improve our financial condition or market value. The failure by management to apply these funds effectively could negatively affect our ability to operate and grow our business. We cannot specify with certainty all of the particular uses for the net proceeds to be received upon the completion of this offering. In addition, the amount, allocation and timing of our actual expenditures will depend upon numerous factors, including any milestone payments due under any strategic partnerships and royalties on sales of any future approved product. Until the net proceeds are used, they may be placed in investments that do not produce significant income or that may lose.

We do not intend to pay dividends in the foreseeable future.

We have never paid cash dividends on our common stock and currently do not plan to pay any cash dividends in the foreseeable future.

It is not possible to predict the aggregate proceeds resulting from sales made under the sales agreement.

Subject to certain limitations in the sales agreement and compliance with applicable law, we have the discretion to deliver a placement notice to Jefferies at any time throughout the term of the sales agreement. The number of shares that are sold through the sales agent after delivering a placement notice will fluctuate based on a number of factors, including the market price of our common stock during the sales period, any limits we may set with the sales agent in any applicable placement notice and the demand for our common stock. Because the price per share of each share sold pursuant to the sales agreement will fluctuate over time, it is not currently possible to predict the aggregate proceeds to be raised in connection with sales under the sales agreement.

Sales of common stock offered hereby will be in “at the market offerings,” and investors who buy shares at different times will likely pay different prices.

Investors who purchase shares in this offering at different times will likely pay different prices, and accordingly may experience different levels of dilution and different outcomes in their investment results. We

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will have discretion, subject to market demand, to vary the timing, prices and number of shares sold in this offering. In addition, subject to the final determination by our board of directors or any restrictions we may place in any applicable placement notice delivered to the sales agent, there is no minimum or maximum sales price for shares to be sold in this offering. Investors may experience a decline in the value of the shares they purchase in this offering as a result of sales made at prices lower than the prices they paid.

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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement and the documents we have filed with the SEC that are incorporated by reference contain “forward-looking statements” within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act. All statements other than statements of historical facts contained in this prospectus supplement, including any statements regarding our future results of operations and financial position, business strategy, product candidates, planned preclinical and nonclinical studies and clinical trials, results of preclinical and nonclinical studies, clinical trials, research and development costs, regulatory approvals, timing and likelihood of success, as well as plans and objectives of management for future operations, are forward-looking statements. These statements involve known and unknown risks, uncertainties, and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance, or achievements expressed or implied by the forward-looking statements.

•

the sufficiency of our existing cash to fund our future operating expenses and capital expenditure requirements;

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the accuracy of our estimates regarding expenses, capital requirements and needs for additional financing;

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our use of the net proceeds from this offering and financing activities;

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the ability of our ongoing and planned clinical trials to be sufficient for regulatory approval in the United States and other territories;

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our ability to commence studies of epetraborole in additional patient populations, which regulatory authorities may not allow or authorize or may delay allowing or authorizing;

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the translation of our preclinical results and data and early clinical trial results, in particular relating to safety, efficacy and durability, into future clinical trial results;

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our ability to retain the continued service of our key professionals and to identify, hire, and retain additional qualified professionals;

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our ability to advance our initial product candidates and any other product candidates we may develop into, and successfully complete, clinical trials;

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the timing of and our ability to obtain and maintain regulatory approvals for our initial product candidates and any other product candidates we may develop;

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the commercialization of our initial product candidates and any other product candidates we may develop, if approved;

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the ability of epetraborole, if approved, to successfully compete with other therapies, including therapies currently in development;

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the size of the market opportunity for epetraborole or any other product candidates we may develop in each of the diseases we target;

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the pricing, coverage, and reimbursement of epetraborole, if approved;

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the implementation of our business model, strategic plans for our business, and our initial product candidates and any other product candidates we may develop;

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the scope of protection we are able to establish and maintain for intellectual property rights covering epetraborole and any other product candidates we may develop;

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our ability to identify additional product candidates and advance them into clinical development;

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our financial performance;

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developments relating to our competitors and our industry;

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our expectations regarding the period during which we will qualify as an emerging growth company under the JOBS Act.

We have based these forward-looking statements largely on our current expectations and projections about our business, the industry in which we operate and financial trends that we believe may affect our business, financial condition, results of operations, and prospects and these forward-looking statements are not guarantees of future performance or development. These forward-looking statements are subject to a number of risks, uncertainties, and assumptions. We discuss in greater detail many of these risks, uncertainties, and assumptions under the heading “Risk Factors” contained in this prospectus supplement and the documents incorporated by reference, in any free writing prospectuses we may authorize for use in connection with this offering, and in our most recent Annual Report on Form 10-K and in our most recent Quarterly Report on Form 10-Q, as updated by our subsequent filings with the SEC, which are incorporated by reference into this prospectus supplement in their entirety. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified, you should not rely on these forward-looking statements as predictions of future events. The events and circumstances reflected in our forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the forward-looking statements. Also, these forward-looking statements represent our estimates and assumptions only as of the date of the document containing the applicable statement. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, or otherwise.

In addition, statements that “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this prospectus supplement, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain, and you are cautioned not to unduly rely upon these statements.

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USE OF PROCEEDS

We may issue and sell shares of our common stock having an aggregate gross sales proceeds of up to $80,000,000 from time to time (before deducting sales agent commissions and expenses). Because there is no minimum offering amount required pursuant to the sales agreement with Jefferies, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. Actual net proceeds will depend on the number of shares we sell and the prices at which such sales occur. There can be no assurance that we will sell any shares under or fully utilize the sales agreement with Jefferies as a source of financing.

We currently intend to use the net proceeds from the sale of the common stock offered by us hereunder, if any, primarily to fund the research and development of our product candidates and for working capital and general corporate purposes. We may also use a portion of the net proceeds to acquire or invest in businesses and products that are complementary to our own, although we have no current plans, commitments or agreements with respect to any acquisitions.

The amounts and timing of our use of the net proceeds from this offering will depend on a number of factors, such as the timing and progress of our research and development efforts, the timing and progress of any partnering and commercialization efforts, technological advances and the competitive environment for our products. As of the date of this prospectus supplement, we cannot specify with certainty all of the particular uses for the net proceeds to us from the sale of the securities offered by us hereunder. Accordingly, our management will have broad discretion in the timing and application of these proceeds. Pending application of the net proceeds as described above, we intend to temporarily invest the proceeds in short-term, investment-grade, interest-bearing instruments.

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DILUTION

If you invest in our common stock in this offering, your ownership interest will be diluted to the extent of the difference between the public offering price per share of common stock and the as adjusted net tangible book value per share immediately after this offering.

As of December 31, 2025, we had a historical net tangible book value of $53.1 million, or $1.94 per share of common stock based on 27,413,171 shares of our common stock outstanding. Our historical net tangible book value per share represents total tangible assets, less total liabilities, divided by the number of shares of common stock outstanding as of December 31, 2025.

After giving effect to the assumed sale of our common stock under the sales agreement in the aggregate amount of $80,000,000 at an assumed offering price of $3.34 per share, the last reported sale price of our common stock on the Nasdaq Global Select Market on April 8, 2026, and after deducting commissions and estimated aggregate offering expenses payable by us, our as adjusted net tangible book value as of December 31, 2025 would have been $130.5 million, or $2.54 per share of common stock. This represents an immediate increase in as adjusted net tangible book value of $0.60 per share to our existing stockholders and an immediate dilution in net tangible book value of $0.80 per share to new investors. We determine dilution by subtracting our as adjusted net tangible book value per share after this offering from the amount of cash paid by an investor for a share of common stock in this offering. The following table illustrates this dilution on a per share basis:


Assumed public offering price per share			$	3.34
Historical net tangible book value per share as of December 31, 2025	$	1.94
Increase in net tangible book value per share attributable to this offering	$	0.60

As adjusted net tangible book value per share as of December 31, 2025, after giving effect to this offering			$	2.54

Dilution per share to new investors purchasing shares in this offering			$	0.80

The table above assumes for illustrative purposes that an aggregate of 23,952,095 shares of our common stock are sold under the sales agreement at a price of $3.34 per share, the last reported sale price of our common stock on the Nasdaq Global Select Market on April 8, 2026, for aggregate gross proceeds of $80,000,000. The shares subject to the sales agreement are being sold from time to time at various prices.

An increase of $1.00 per share in the price at which the shares are sold from the assumed offering price of $3.34 per share, assuming common stock in the aggregate amount of $80,000,000 is sold at that price, would increase our as adjusted net tangible book value per share after the offering to $2.85 per share and would increase the dilution in net tangible book value per share to new investors in this offering to $1.49 per share, after deducting commissions and estimated aggregate offering expenses payable by us. A decrease of $1.00 per share in the price at which the shares are sold from the assumed offering price of $3.34 per share, assuming common stock in the aggregate amount of $80,000,000 is sold at that price, would decrease our as adjusted net tangible book value per share after the offering to $2.12 per share and would decrease the dilution in net tangible book value per share to new investors in this offering to $0.22 per share, after deducting commissions and estimated aggregate offering expenses payable by us. This information is supplied for illustrative purposes only and will change based on the actual offering price, the actual number of shares sold and other terms of the offering determined at the time shares of our common stock are sold pursuant to this prospectus supplement.

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5,466,222 shares of common stock issuable upon the exercise of outstanding stock options with a weighted-average exercise price of $6.56 per share;

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856,160 shares of common stock issuable upon the vesting and settlement of outstanding restricted stock units;

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2,952,000 shares of common stock issuable upon the exercise of outstanding pre-funded warrants, at an exercise price of $0.00001 per share;

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To the extent that outstanding options or pre-funded warrants have been or are exercised, outstanding restricted stock units have vested and settled or vest and settle, or other shares are issued, investors purchasing shares in this offering could experience further dilution. In addition, we may choose to raise additional capital due to market conditions or strategic considerations, including for potential acquisition or in-licensing opportunities, even if we believe we have sufficient funds for our current or future operating plans. To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our stockholders.

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PLAN OF DISTRIBUTION

We have entered into a sales agreement with Jefferies, under which we may offer and sell up to $80,000,000 of our shares of common stock from time to time through Jefferies acting as agent. Sales of our shares of common stock, if any, under this prospectus supplement and the accompanying prospectus will be made by any method that is deemed to be an “at the market offering” as defined in Rule 415(a)(4) under the Securities Act.

Each time we wish to issue and sell our shares of common stock under the sales agreement, we will notify Jefferies of the number of shares to be issued, the dates on which such sales are anticipated to be made, any limitation on the number of shares to be sold in any one day and any minimum price below which sales may not be made. Once we have so instructed Jefferies, unless Jefferies declines to accept the terms of such notice, Jefferies has agreed to use its commercially reasonable efforts consistent with its normal trading and sales practices to sell such shares up to the amount specified on such terms. The obligations of Jefferies under the sales agreement to sell our shares of common stock are subject to a number of conditions that we must meet.

The settlement of sales of shares between us and Jefferies is generally anticipated to occur on the first trading day following the date on which the sale was made. Sales of our shares of common stock as contemplated in this prospectus supplement will be settled through the facilities of The Depository Trust Company or by such other means as we and Jefferies may agree upon. There is no arrangement for funds to be received in an escrow, trust or similar arrangement.

We will pay Jefferies a commission of up to 3.0% of the aggregate gross proceeds we receive from each sale of our shares of common stock. Because there is no minimum offering amount required as a condition to close this offering, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. We estimate that the total expenses for the offering, excluding any commissions payable to Jefferies under the terms of the sales agreement, will be approximately $200,000. The remaining sale proceeds, after deducting any other transaction fees, will equal our net proceeds from the sale of such shares.

Jefferies will provide written confirmation to us before the open on the Nasdaq Global Select Market on the day following each day on which our shares of common stock are sold under the sales agreement. Each confirmation will include the number of shares sold on that day, the aggregate gross proceeds of such sales and the proceeds to us.

In connection with the sale of our shares of common stock on our behalf, Jefferies will be deemed to be an “underwriter” within the meaning of the Securities Act, and the compensation of Jefferies will be deemed to be underwriting commissions or discounts. We have agreed to indemnify Jefferies against certain civil liabilities, including liabilities under the Securities Act. We have also agreed to contribute to payments Jefferies may be required to make in respect of such liabilities.

We and Jefferies may each terminate the sales agreement at any time upon ten days’ prior written notice, subject to the terms of the sales agreement.

This summary of the material provisions of the sales agreement does not purport to be a complete statement of its terms and conditions. A copy of the sales agreement is filed as an exhibit to the registration statement of which this prospectus supplement forms a part and incorporated by reference in this prospectus supplement.

Jefferies and its affiliates have provided, and may in the future provide various investment banking, commercial banking, financial advisory and other financial services for us and our affiliates, for which services they have received, and may in the future receive customary fees. In the course of its business, Jefferies may actively trade our securities for its own account or for the accounts of customers, and, accordingly, Jefferies may at any time hold long or short positions in such securities.

This prospectus supplement and the accompanying prospectus in electronic format may be made available on a website maintained by Jefferies, and Jefferies may distribute this prospectus supplement and the accompanying prospectus electronically.

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LEGAL MATTERS

Latham & Watkins LLP will pass upon the validity of the shares of our common stock offered hereby. Jefferies is being represented by Davis Polk & Wardwell LLP, Redwood City, California in connection with the offering.

EXPERTS

The financial statements incorporated in this Prospectus Supplement by reference to the Annual Report on Form 10-K for the year ended December 31, 2025 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

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WHERE YOU CAN FIND MORE INFORMATION

This prospectus supplement and the accompanying prospectus are part of the registration statement on Form S-3 we filed with the SEC under the Securities Act and do not contain all the information set forth in the registration statement and the exhibits to the registration statement. Whenever a reference is made in this prospectus supplement or the accompanying prospectus to any of our contracts, agreements or other documents, the reference may not be complete and you should refer to the exhibits that are a part of the registration statement or the exhibits to the reports or other documents incorporated by reference into this prospectus supplement or the accompanying prospectus for a copy of such contract, agreement or other document. Neither we nor any agent, underwriter or dealer has authorized any person to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus supplement or the accompanying prospectus is accurate as of any date other than the date on the front page of this prospectus supplement or the accompanying prospectus, regardless of the time of delivery of this prospectus supplement and the accompanying prospectus or any sale of the securities offered by this prospectus supplement and the accompanying prospectus. Because we are subject to the information and reporting requirements of the Exchange Act, we file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public over the internet at the SEC’s website at http://www.sec.gov.

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INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to incorporate by reference information from other documents that we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus supplement and the accompanying prospectus. Information in this prospectus supplement supersedes information incorporated by reference that we filed with the SEC prior to the date of this prospectus supplement, while information that we file later with the SEC will automatically update and supersede the information in this prospectus supplement and the accompanying prospectus. We incorporate by reference into this prospectus supplement, the accompanying prospectus and the registration statement of which this prospectus supplement is a part the information or documents listed below that we have filed with the SEC:

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Our Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the SEC on March 17, 2026.

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Our Current Reports on Form 8-K filed (other than information furnished rather than filed) with the SEC on January 29, 2026, March 10, 2026, March 20, 2026 and April 9, 2026.

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The description of our common stock which is contained in our Registration Statement on Form 8-A filed on March 22, 2022 (File No. 001-41331) under the Exchange Act, as updated by Exhibit 4.3 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the SEC on March 17, 2026, including any amendment or report filed for the purpose of updating such description.

We also incorporate by reference any future filings (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items unless such Form 8-K expressly provides to the contrary) made with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, including those made after the date of the initial filing of the registration statement of which this prospectus supplement is a part and prior to effectiveness of such registration statement, until we file a post-effective amendment that indicates the termination of the offering of the securities made by this prospectus supplement and the accompanying prospectus, which will become a part of this prospectus supplement and the accompanying prospectus from the date that such documents are filed with the SEC. Information in such future filings updates and supplements the information provided in this prospectus supplement and the accompanying prospectus. Any statements in any such future filings will automatically be deemed to modify and supersede any information in any document we previously filed with the SEC that is incorporated or deemed to be incorporated herein by reference to the extent that statements in the later-filed document modify or replace such earlier statements. We will furnish without charge to each person, including any beneficial owner, to whom this prospectus supplement and the accompanying prospectus is delivered, upon written or oral request, a copy of any or all of the documents incorporated by reference into this prospectus supplement and the accompanying prospectus but not delivered with the prospectus supplement and the accompanying prospectus, including exhibits that are specifically incorporated by reference into such documents. You should direct any requests for documents to:

AN2 Therapeutics, Inc.

Attn: Chief Legal Officer

1300 El Camino Real, Suite 100

Menlo Park, California 94025

(650) 331-9090

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$80,000,000

LOGO

Common Stock

PROSPECTUS SUPPLEMENT

Jefferies

, 2026

Subject to Completion, dated April 9, 2026

PROSPECTUS SUPPLEMENT

LOGO

14,035,104 Shares of

Common Stock

Offered by the Selling Securityholders

This prospectus supplement relates to the proposed resale or other disposition from time to time of up to an aggregate of 14,035,104 shares of common stock by the selling securityholders named in this prospectus supplement (the “selling securityholders”), which consists of: (i) 8,245,611 shares of our common stock and (ii) 5,789,493 shares of our common stock issuable upon the exercise of pre-funded warrants to purchase shares of our common stock. We are registering the offer and sale of the shares covered by this prospectus supplement to satisfy registration rights we granted to the selling securityholders pursuant to that certain registration rights agreement, dated March 10, 2026, by and among us and the selling securityholders in connection with the selling securityholders’ purchase of shares of common stock or, in lieu thereof, pre-funded warrants to purchase shares of common stock in a private placement (the “Registration Rights Agreement”).

Our common stock is listed on the Nasdaq Global Select Market under the symbol “ANTX.” On April 8, 2026, the last reported sale price of our common stock was $3.34 per share.

The selling securityholders may, from time to time, sell, transfer, or otherwise dispose of any or all of their shares of common stock covered by this prospectus supplement on any stock exchange, market, or trading facility on which the shares are traded or in private transactions. These dispositions may be at fixed prices, at prevailing market prices at the time of sale, at prices related to the prevailing market price, at varying prices determined at the time of sale, or at negotiated prices. See “Plan of Distribution” beginning on page S-12 for more information about how the selling securityholders may sell or dispose of their shares of common stock hereunder.

We are not selling any shares of our common stock under this prospectus supplement and will not receive any proceeds from the sale or other disposition of the shares of common stock covered by this prospectus supplement by the selling securityholders. Upon any exercise of the pre-funded warrants by payment of cash, however, we will receive the nominal cash exercise price paid by the holders of the pre-funded warrants. We intend to use those proceeds, if any, for general corporate purposes. The selling securityholders will bear all costs, commissions and discounts, if any, attributable to the sales of the shares of common stock covered by this prospectus supplement. We will bear the fees and expenses incurred in effecting the registration of the shares of common stock covered by this prospectus supplement, including, without limitation, all registration, filing, and printing fees and expenses, and fees and expenses of our counsel and our independent registered public accounting firm.

We may amend or supplement this prospectus supplement from time to time by filing amendments or supplements as required. You should read the entire prospectus supplement and any amendments or supplements carefully before you make your investment decision.

Our business and an investment in our common stock involve significant risks. These risks are described under the caption “Risk Factors” beginning on page S-5 of this prospectus supplement and in the documents incorporated by reference into this prospectus supplement.

, 2026.


TABLE OF CONTENTS
ABOUT THIS PROSPECTUS SUPPLEMENT			S-1
PROSPECTUS SUPPLEMENT SUMMARY			S-3
RISK FACTORS			S-5
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS			S-6
USE OF PROCEEDS			S-8
THE SELLING SECURITYHOLDERS			S-9
PLAN OF DISTRIBUTION			S-12
LEGAL MATTERS			S-15
EXPERTS			S-15
WHERE YOU CAN FIND MORE INFORMATION			S-16
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE			S-17

ABOUT THIS PROSPECTUS SUPPLEMENT

This prospectus supplement is part of a registration statement on Form S-3 that we have filed with the Securities and Exchange Commission, or SEC, utilizing a “shelf” registration process. By using a shelf registration statement, the selling securityholders named in a prospectus supplement may, from time to time, offer and sell our common stock in one or more offerings or resales. The accompanying prospectus provides you with a general description of our securities, which the selling securityholders may offer and sell pursuant to this prospectus supplement. We and the selling securityholders provide information to you about this offering of shares of our common stock in this prospectus supplement, which describes the specific details regarding this offering. If information in this prospectus supplement is inconsistent with the information in the accompanying prospectus or the documents incorporated by reference in this prospectus supplement filed prior to the date of this prospectus supplement, you should rely on this prospectus supplement. However, if any statement in one of these documents is inconsistent with a statement in another document having a later date—for example, a document incorporated by reference in this prospectus supplement—the statement in the document having the later date modifies or supersedes the earlier statement as our business, financial condition, results of operations and prospects may have changed since the earlier dates.

Neither we, nor the selling securityholders, have authorized any other person to provide you with any information other than that contained in or incorporated by reference in this prospectus supplement, the accompanying prospectus or any free writing prospectus prepared by or on behalf of us or to which we have referred you. Neither we nor the selling securityholders take responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We are not, and the selling securityholders are not, making an offer to sell or soliciting an offer to buy our securities in any jurisdiction in which an offer or solicitation is not authorized or in which the person making that offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make an offer or solicitation. You should assume that the information appearing in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein and therein, and in any free writing prospectus that we may authorize for use in connection with this offering, is accurate only as of the date of those respective documents. Our business, financial condition, results of operations and prospects may have changed since those dates. You should read this prospectus supplement, the accompanying prospectus, the documents incorporated by reference herein and therein as described under the headings “Where You Can Find More Information” and “Incorporation of Certain Information by Reference,” and any free writing prospectus that we may authorize for use in connection with this offering, in their entirety before making an investment decision. These documents contain important information that you should consider when making your investment decision.

We and the selling securityholders are offering to sell, and seeking offers to buy, shares of common stock only in jurisdictions where offers and sales are permitted. The distribution of this prospectus supplement and the offering of our common stock in certain jurisdictions may be restricted by law. Persons outside the United States who come into possession of this prospectus supplement must inform themselves about, and observe any restrictions relating to, the offering of our common stock and the distribution of this prospectus supplement outside the United States. This prospectus supplement does not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.

We obtained the industry and market data in this prospectus supplement from our own research as well as from industry and general publications, surveys and studies conducted by third parties. These data involve a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. In addition, projections, assumptions and estimates of our future performance and the future performance of the industry in which we operate are necessarily subject to a high degree of uncertainty and risk due to a variety of factors, including those described in “Risk Factors” and elsewhere in this prospectus supplement and documents incorporated by reference into this prospectus supplement. These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties and by us.

S-1

supplement and the accompanying prospectus are a part, and you may obtain copies of those documents as described below under the headings “Where You Can Find More Information” and “Incorporation of Certain Information by Reference.”

S-2

PROSPECTUS SUPPLEMENT SUMMARY

AN2 Therapeutics, Inc.

Overview

Corporate Information

We were incorporated in February 2017 as a Delaware corporation and launched operations in November 2019. Our principal executive offices are located at 1300 El Camino Real, Suite 100, Menlo Park, California 94025 and our telephone number is (650) 331-9090. Our website address is www.an2therapeutics.com. The information contained on, or that can be accessed through, our website will not be deemed to be incorporated by reference into this prospectus supplement and does not constitute part of this prospectus supplement. Our website address is included in this prospectus supplement as an inactive textual reference only.

Implications of Being an Emerging Growth Company and a Smaller Reporting Company

S-3

S-4

RISK FACTORS

S-5

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

•

the sufficiency of our existing cash to fund our future operating expenses and capital expenditure requirements;

•

the accuracy of our estimates regarding expenses, capital requirements and needs for additional financing;

•

our use of the net proceeds from financing activities;

•

the ability of our ongoing and planned clinical trials to be sufficient for regulatory approval in the United States and other territories;

•

our ability to commence studies of epetraborole in additional patient populations, which regulatory authorities may not allow or authorize or may delay allowing or authorizing;

•

the translation of our preclinical results and data and early clinical trial results, in particular relating to safety, efficacy and durability, into future clinical trial results;

•

our ability to retain the continued service of our key professionals and to identify, hire, and retain additional qualified professionals;

•

our ability to advance our initial product candidates and any other product candidates we may develop into, and successfully complete, clinical trials;

•

the timing of and our ability to obtain and maintain regulatory approvals for our initial product candidates and any other product candidates we may develop;

•

the commercialization of our initial product candidates and any other product candidates we may develop, if approved;

•

the ability of epetraborole, if approved, to successfully compete with other therapies, including therapies currently in development;

•

the size of the market opportunity for epetraborole or any other product candidates we may develop in each of the diseases we target;

•

the pricing, coverage, and reimbursement of epetraborole, if approved;

S-6

•

the implementation of our business model, strategic plans for our business, and our initial product candidates and any other product candidates we may develop;

•

the scope of protection we are able to establish and maintain for intellectual property rights covering epetraborole and any other product candidates we may develop;

•

our ability to identify additional product candidates and advance them into clinical development;

•

our financial performance;

•

developments relating to our competitors and our industry;

•

our expectations regarding the period during which we will qualify as an emerging growth company under the JOBS Act.

We have based these forward-looking statements largely on our current expectations and projections about our business, the industry in which we operate and financial trends that we believe may affect our business, financial condition, results of operations, and prospects and these forward-looking statements are not guarantees of future performance or development. These forward-looking statements are subject to a number of risks, uncertainties, and assumptions. We discuss in greater detail many of these risks, uncertainties, and assumptions under the heading “Risk Factors” contained in this prospectus supplement and the documents incorporated by reference, in any free writing prospectuses we may authorize for use in connection with this offering, and in our most recent Annual Report on Form 10-K and in our most recent Quarterly Report on Form 10-Q, as updated by our subsequent filings with the SEC, which are incorporated by reference into this prospectus supplement in their entirety. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified, you should not rely on these forward-looking statements as predictions of future events. The events and circumstances reflected in our forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the forward-looking statements. Also, these forward-looking statements represent our estimates and assumptions only as of the date of the document containing the applicable statement. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, or otherwise.

In addition, statements that “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this prospectus supplement, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain, and you are cautioned not to unduly rely upon these statements.

S-7

USE OF PROCEEDS

We will not receive any of the proceeds from the sale of shares of our common stock being offered by the selling securityholders. Upon any exercise of the pre-funded warrants by payment of cash, however, we will receive the nominal cash exercise price paid by the holders of the pre-funded warrants. We intend to use those proceeds, if any, for general corporate purposes.

The selling securityholders will bear all costs, commissions and discounts, if any, attributable to the sales of the shares of common stock covered by this prospectus supplement. We will bear the fees and expenses incurred in effecting the registration of the shares of common stock covered by this prospectus supplement, including, without limitation, all registration, filing, and printing fees and expenses, and fees and expenses of our counsel and our independent registered public accounting firm.

S-8

THE SELLING SECURITYHOLDERS

This prospectus supplement relates to the proposed resale or other disposition from time to time of up to an aggregate of 14,035,104 shares of common stock by the selling securityholders, which consists of: (i) 8,245,611 shares of our common stock and (ii) 5,789,493 shares of our common stock issuable upon the exercise of pre-funded warrants to purchase shares of our common stock. We are registering the offer and sale of the shares covered by this prospectus supplement pursuant to the Registration Rights Agreement.

The following table sets forth information concerning the shares of common stock that may be offered from time to time by each of the selling securityholders. The number of shares beneficially owned by the selling securityholders is determined under rules issued by the SEC. Under these rules, beneficial ownership includes any shares as to which each of the selling securityholders has sole or shared voting power or investment power. Percentage ownership is based on 35,949,314 shares of common stock outstanding as of March 31, 2026, and, for each selling securityholder that owns securities that are exercisable or convertible into shares of common stock within 60 days of March 31, 2026, considers such shares of common stock outstanding, although these shares of common stock are not considered outstanding for purposes of computing the percentage ownership of any other selling securityholder.

For purposes of this table, we have assumed that the selling securityholders will have sold all of the shares of common stock covered by this prospectus supplement upon the completion of the offering (including all shares of common stock issuable upon exercise of pre-funded warrants relating to such shares).

The number of shares of our common stock offered for sale by the selling securityholders as set forth in the column below titled “Number of Shares Offered” does not take into account any contractual limitations contained in any securities, including the pre-funded warrants, that may restrict a holder (together with its affiliates) from beneficially owning in excess of a specified percentage of our common stock.

The information in the following table has been provided to us by or on behalf of the selling securityholders and the selling securityholders may have sold, transferred or otherwise disposed of all or a portion of the shares of common stock after the date on which they provided us with information regarding their securities. Each of the selling securityholders listed has sole voting and investment power with respect to the shares beneficially owned by the selling securityholder unless noted otherwise. The selling securityholders may sell all, some or none of their shares of common stock in this offering. See the section titled “Plan of Distribution.”


	Common Stock Beneficially Owned Prior to this Offering					Number of Shares Offered		Common Stock Beneficially Owned Upon Completion of this Offering
Selling Securityholder	Number		Percentage			Number		Number		Percentage
Ally Bridge MedAlpha Master Fund L.P.⁽¹⁾		526,315		1.46	%		526,315		—		—
Atlas Private Holdings (Cayman) Ltd.⁽²⁾		1,052,631		2.93	%		1,052,631		—		—
Boxer Capital Master Fund, LP⁽³⁾		749,035		2.08	%		614,035		135,000		*
Coastlands Capital Partners LP⁽⁴⁾		3,649,032		9.99	%		3,508,784		4,038,464		9.99	%
Commodore Capital Master LP⁽⁵⁾		3,730,917		9.99	%		4,561,410		53,012			*
Entities affiliated with Prosight Management, L.P.⁽⁶⁾		350,877			*		350,877		—		—
Entities affiliated with Spruce Street Capital⁽⁷⁾		1,661,073		4.62	%		614,035		1,047,038		2.91	%
Stonepine Capital, LP⁽⁸⁾		713,845		1.99	%		350,877		362,968		1.01	%
Entities affiliated with Vivo⁽⁹⁾		3,153,640		8.77	%		2,456,140		697,500		1.94	%

*	Less than 1%.

(1)	Consists of 526,315 shares of common stock held by Ally Bridge MedAlpha Master Fund L.P. (“MedAlpha”). Mr. Fan Yu is the sole shareholder of ABG Management Ltd., which is the sole member of Ally Bridge Group (NY) LLC, which manages investments of MedAlpha. As such, each of the foregoing

S-9

entities and Mr. Fan Yu may be deemed to share beneficial ownership of the shares held by MedAlpha. Each of them disclaims any such beneficial ownership. The address of MedAlpha is c/o Ally Bridge Group (NY) LLC, 430 Park Avenue, 12th, Floor, New York, NY 10022.

(2)

Consists of 1,052,631 shares of common stock held by Atlas Private Holdings (Cayman) Ltd. Balyasny Asset Management L.P. is the investment adviser of Atlas Private Holdings (Cayman) Ltd. Dmitry Balyasny, via intermediate entities, manages Balyasny Asset Management L.P. and has voting and investment control over the reported securities. The address of Atlas Private Holdings (Cayman) Ltd. is c/o Balyasny Asset Management L.P., 444 West Lake Street, 50th Floor, Chicago, IL 60606.

(3)	Consist of 749,035 shares of common stock held by Boxer Capital Master Fund, LP. The address of Boxer Capital Master Fund, LP is 12860 El Camino Real, Ste 300, San Diego, CA 92130.

(4)

Beneficial ownership prior to this offering consists of (i) 3,071,492 shares of common stock and (ii) 577,540 shares of common stock issuable upon the exercise of pre-funded warrants, in each case held by Coastlands Capital Partners LP (“Coastlands Capital”). The pre-funded warrants held by Coastlands prohibit the exercise thereof if, after giving effect to such exercise, the beneficial ownership of Coastlands Capital, its affiliates and any person whose beneficial ownership would be attributable to such entities, would exceed 9.99%, which percentage may be increased or decreased, but not in excess of 19.99%, upon at least 61 days’ prior notice. The foregoing excludes 5,731,244 shares of common stock underlying the pre-funded warrants, which are subject to such beneficial ownership limitations. Beneficial ownership upon completion of this offering gives effect to the sale in this offering of 3,508,784 shares of common stock issuable upon the exercise of pre-funded warrants. Coastlands Capital LP (“Coastlands”) is the investment adviser to Coastlands Capital and Coastlands Capital GP LLC (“Coastlands GP LLC”) is the general partner of Coastlands Capital. Coastlands Capital LLC (“Coastlands GP”, and together with Coastlands, Coastlands Capital and Coastlands GP LLC, the “Coastlands Entities”) is the general partner of Coastlands. Matthew D. Perry is the control person of the Coastlands Entities. The Coastlands Entities and Mr. Perry each disclaim membership in a group. The Coastlands Entities and Mr. Perry also each disclaim beneficial ownership of the shares of common stock except to the extent of such entity or person’s pecuniary interest therein. The address of the Coastlands Entities and Mr. Perry is 601 California St., Suite 1210, San Francisco, CA 94108.

(5)

Beneficial ownership prior to this offering consists of (i) 2,333,713 shares of common stock and (ii) 1,397,204 shares of common stock issuable upon the exercise of a pre-funded warrant, in each case held by Commodore Capital Master LP. The pre-funded warrant held by Commodore Capital Master LP prohibits the exercise thereof if, after giving effect to such exercise, the beneficial ownership of Commodore Capital Master LP, its affiliates and any person whose beneficial ownership would be attributable to such entities, would exceed 9.99%, which percentage may be increased or decreased, but not in excess of 19.99%, upon at least 61 days’ prior notice. The foregoing excludes 883,505 shares of common stock underlying the pre-funded warrant, which is subject to such beneficial ownership limitation. Beneficial ownership upon completion of this offering gives effect to the sale in this offering of an aggregate of 2,280,701 shares of common stock and 2,280,709 shares of common stock issuable upon the exercise of pre-funded warrants. Commodore Capital LP is the investment manager to Commodore Capital Master LP and may be deemed to beneficially own the shares held by Commodore Capital Master LP. Michael Kramarz and Robert Egen Atkinson are the managing partners of Commodore Capital LP and exercise investment discretion with respect to these shares. The principal business address of Commodore Capital LP is 444 Madison Avenue, 35th Floor, New York, NY 10022.

(6)

Consists of (i) 48,456 shares of common stock held by Belmont Harbor Master Fund, LP, (ii) 7,158 shares of common stock held by West Tower Partners, SPC, (iii) 78,210 shares of common stock held by Prosight Plus Fund, LP (“Prosight Plus Fund”) and (iv) 16,246 shares of common stock held by Prosight Fund, LP (“Prosight Fund”). Each of Prosight Management, LP (“Prosight Management”), Prosight Partners, LLC (“Prosight Partners”) and W. Lawrence Hawkins has shared voting and dispositive power over all of such shares. Prosight Management is the general partner and investment manager of, and may be deemed to indirectly beneficially own securities owned by, Prosight Fund and Prosight Plus Fund. Prosight Management is a sub-advisor for certain separate managed accounts (collectively, the “Managed Accounts”) and may be deemed to indirectly beneficially own securities owned by the Managed Accounts. Prosight Partners is the general partner of, and may be deemed to beneficially own, securities beneficially owned by

S-10

Prosight Management. Mr. Hawkins is the sole manager of, and may be deemed to beneficially own securities beneficially owned by, Prosight Partners. Prosight Fund disclaims beneficial ownership of the shares of common stock held by each of the Managed Accounts, Prosight Plus Fund and Mr. Hawkins. Prosight Plus Fund disclaims beneficial ownership of the shares of common stock held by each of the Managed Accounts, Prosight Fund, and Mr. Hawkins. Mr. Hawkins disclaims beneficial ownership of the shares of common stock held by each of the Managed Accounts, Prosight Fund and Prosight Plus Fund. The address for each of the foregoing named persons is c/o Prosight Management, LP, 5956 Sherry Lane, Suite 1365, Dallas, TX 75225.

(7)

Consists of (i) 291,428 shares of common stock held by a separate account managed by Spruce Street Capital LP (the “Spruce Street Account”) and (ii) 1,369,645 shares of common stock held by Spruce Street Capital Master Fund LP (“Master Fund”, and together with the Spruce Street Account, the “Spruce Funds”). Alex Ryan Rosen and Simon Basseyn are the controlling persons of the Spruce Funds and may be deemed to share voting, investment and dispositive power over the shares held by the Spruce Funds. Messrs. Rosen and Basseyn disclaim beneficial ownership of such shares, except to the extent of any pecuniary interest therein. The principal business address of the Spruce Funds and Messrs. Rosen and Basseyn is 777 Third Avenue, Suite 1704, New York, NY 10017.

(8)

Consists of 713,845 shares held by Stonepine Capital, LP. Jon M. Plexico exercises voting and investment discretion with respect to the securities held by Stonepine Capital, LP and as such may be deemed to beneficially own the securities held by Stonepine Capital, LP. The address of Stonepine Capital, LP and Mr. Plexico is 2900 NW Clearwater Drive, Ste 100-11, Bend, OR 97703.

(9)

Consists of (i) 2,864,346 shares of common stock held by Vivo Opportunity Fund Holdings, L.P. and (ii) 289,294 shares of common stock held by Vivo Opportunity Cayman Fund, L.P. Vivo Opportunity, LLC is the general partner of Vivo Opportunity Fund Holdings, L.P. and Vivo Opportunity Cayman, LLC is the general partner of Vivo Opportunity Cayman Fund, L.P. The business address for Vivo Opportunity Fund Holdings, L.P., Vivo Opportunity, LLC, Vivo Opportunity Cayman Fund, L.P. and Vivo Opportunity Cayman, LLC is 192 Lytton Avenue, Palo Alto, CA 94301.

S-11

PLAN OF DISTRIBUTION

The selling securityholders, which as used herein includes donees, pledgees, transferees or other successors-in-interest selling shares of common stock or interests in shares of common stock received after the date of this prospectus supplement from a selling securityholder as a gift, pledge, partnership distribution or other transfer, may, from time to time, sell, transfer or otherwise dispose of any or all of their shares of common stock or interests in shares of common stock on any stock exchange, market or trading facility on which the shares are traded or in private transactions. These dispositions may be at fixed prices, at prevailing market prices at the time of sale, at prices related to the prevailing market price, at varying prices determined at the time of sale, or at negotiated prices.

The selling securityholders may use any one or more of the following methods when disposing of shares or interests therein:

•

distributions to members, partners, stockholders or other equityholders of the selling securityholders;

•

ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers;

•

block trades in which the broker-dealer will attempt to sell the shares as agent, but may position and resell a portion of the block as principal to facilitate the transaction;

•

purchases by a broker-dealer as principal and resale by the broker-dealer for its account;

•

an exchange distribution in accordance with the rules of the applicable exchange;

•

privately negotiated transactions;

•

short sales and settlement of short sales entered into after the effective date of the registration statement of which this prospectus supplement is a part;

•

through the writing or settlement of options or other hedging transactions, whether through an options exchange or otherwise;

•

broker-dealers may agree with the selling securityholders to sell a specified number of such shares at a stipulated price per share;

•

a combination of any such methods of sale; and

•

any other method permitted pursuant to applicable law.

The selling securityholders may, from time to time, pledge or grant a security interest in some or all of the shares of common stock owned by them and, if they default in the performance of their secured obligations, the pledgees or secured parties may offer and sell the shares of common stock, from time to time, under this prospectus supplement, or under an amendment to this prospectus supplement under Rule 424(b)(3) or other applicable provision of the Securities Act, amending the list of selling securityholders to include the pledgee, transferee or other successors in interest as selling securityholders under this prospectus supplement. The selling securityholders also may transfer the shares of common stock in other circumstances, in which case the transferees, pledgees or other successors in interest will be the selling securityholders for purposes of this prospectus supplement.

In connection with the sale of our common stock or interests therein, the selling securityholders may enter into hedging transactions with broker-dealers or other financial institutions, which may in turn engage in short sales of the common stock in the course of hedging the positions they assume. The selling securityholders may also sell shares of our common stock short and deliver these securities to close out their short positions, or loan or pledge the common stock to broker-dealers that in turn may sell these securities. The selling securityholders may also enter into option or other transactions with broker-dealers or other financial institutions or the creation of one or more derivative securities which require the delivery to such broker-dealer or other financial institution

S-12

of shares offered by this prospectus supplement, which shares such broker-dealer or other financial institution may resell pursuant to this prospectus supplement (as supplemented or amended to reflect such transaction).

The aggregate proceeds to the selling securityholders from the sale of the common stock offered by them will be the purchase price of the common stock less discounts or commissions, if any. Each of the selling securityholders reserves the right to accept and, together with their agents from time to time, to reject, in whole or in part, any proposed purchase of common stock to be made directly or through agents. We will not receive any of the proceeds from this offering. Upon any exercise of the pre-funded warrants by payment of cash, however, we will receive the exercise price of the pre-funded warrants.

The selling securityholders also may resell all or a portion of the shares in open market transactions in reliance upon Rule 144 under the Securities Act, provided that they meet the criteria and conform to the requirements of that rule, or another available exemption from the registration requirements under the Securities Act.

The selling securityholders and any underwriters, broker-dealers or agents that participate in the sale of the common stock or interests therein may be “underwriters” within the meaning of Section 2(a)(11) of the Securities Act (it being understood that the selling securityholders shall not be deemed to be underwriters solely as a result of their participation in this offering). Any discounts, commissions, concessions or profit they earn on any resale of the shares may be underwriting discounts and commissions under the Securities Act. Selling securityholders who are “underwriters” within the meaning of Section 2(a)(11) of the Securities Act will be subject to the prospectus delivery requirements of the Securities Act.

To the extent required, the shares of our common stock to be sold, the names of the selling securityholders, the respective purchase prices and public offering prices, the names of any agent, dealer or underwriter, and any applicable commissions or discounts with respect to a particular offer will be set forth in an accompanying prospectus supplement or, if appropriate, a post-effective amendment to the registration statement that includes this prospectus supplement.

In order to comply with the securities laws of some states, if applicable, the common stock may be sold in these jurisdictions only through registered or licensed brokers or dealers. In addition, in some states the common stock may not be sold unless it has been registered or qualified for sale or an exemption from registration or qualification requirements is available and is complied with.

We have advised the selling securityholders that the anti-manipulation rules of Regulation M under the Exchange Act may apply to sales of shares in the market and to the activities of the selling securityholders and their affiliates. In addition, to the extent applicable, we will make copies of this prospectus supplement (as it may be supplemented or amended from time to time) available to the selling securityholders for the purpose of satisfying the prospectus delivery requirements of the Securities Act. The selling securityholders may indemnify any broker-dealer that participates in transactions involving the sale of the shares against certain liabilities, including liabilities arising under the Securities Act.

We have agreed to indemnify the selling securityholders against liabilities, including liabilities under the Securities Act and state securities laws, relating to the registration of the shares offered by this prospectus supplement.

We have agreed with the selling securityholders to use commercially reasonable efforts to cause the registration statement of which this prospectus supplement constitutes a part to become effective and to remain continuously effective until the earlier of: (i) the date on which the selling securityholders shall have resold or otherwise disposed of all the shares covered by this prospectus supplement, (ii) the date on which the shares covered by this prospectus supplement no longer constitute “Registrable Securities” as such term is defined in the Registration Rights Agreement, such that they may be resold by the selling securityholders without registration

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and without regard to any volume or manner-of-sale limitations and without current public information pursuant to Rule 144 under the Securities Act or any other rule of similar effect, and (iii) five years after the date of the Registration Rights Agreement.

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LEGAL MATTERS

Latham & Watkins LLP will pass upon the validity of the shares of our common stock offered hereby.

EXPERTS

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WHERE YOU CAN FIND MORE INFORMATION

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INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

•

Our Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the SEC on March 17, 2026.

•

Our Current Reports on Form 8-K filed (other than information furnished rather than filed) with the SEC on January 29, 2026, March 10, 2026, March 20, 2026 and April 9, 2026.

•

AN2 Therapeutics, Inc.

Attn: Chief Legal Officer

1300 El Camino Real, Suite 100

Menlo Park, California 94025

(650) 331-9090

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LOGO

14,035,104 Shares of

Common Stock

Offered by the Selling Securityholders

PROSPECTUS SUPPLEMENT

, 2026

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14.

Other Expenses of Issuance and Distribution

The following is an estimate of the expenses (all of which are to be paid by the registrant) that we may incur in connection with the securities being registered hereby.


SEC registration fee	$	(1)41,833
FINRA filing fee	$	(2	)
Printing expenses	$	(2	)
Legal fees and expenses	$	(2	)
Accounting fees and expenses	$	(2	)
Blue Sky, qualification fees and expenses	$	(2	)
Transfer agent fees and expenses	$	(2	)
Trustee fees and expenses	$	(2	)
Warrant agent fees and expenses	$	(2	)
Miscellaneous	$	(2	)

Total	$	(2	)

(1)	In accordance with Rule 415(a)(6), includes certain fees previously paid in respect of Unsold Securities previously registered under the registrant’s registration statement on Form S-3 (File No. 333-271174), as further described in the Filing Fee Table included as Exhibit 107 hereto.

(2)	These fees are calculated based on the securities offered and the number of issuances and accordingly cannot be estimated at this time.

Item 15.

Indemnification of Directors and Officers

Subsection (a) of Section 145 of the General Corporation Law of the State of Delaware (the “DGCL”) empowers a corporation to indemnify any person who was or is a party or who is threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative (other than an action by or in the right of the corporation) by reason of the fact that the person is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise, against expenses (including attorneys’ fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by the person in connection with such action, suit or proceeding if the person acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, had no reasonable cause to believe the person’s conduct was unlawful.

Subsection (b) of Section 145 empowers a corporation to indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action or suit by or in the right of the corporation to procure a judgment in its favor by reason of the fact that the person acted in any of the capacities set forth above, against expenses (including attorneys’ fees) actually and reasonably incurred by the person in connection with the defense or settlement of such action or suit if the person acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation, except that no indemnification shall be made in respect of any claim, issue or matter as to which such person shall have been adjudged to be liable to the corporation unless and only to the extent that the Court of Chancery or the court in which such action or suit was brought shall determine upon application that, despite the adjudication of liability but in view of all the circumstances of the case, such person is fairly and reasonably entitled to indemnity for such expenses which the Court of Chancery or such other court shall deem proper.

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Section 145 further provides that to the extent a director or officer of a corporation has been successful on the merits or otherwise in the defense of any action, suit or proceeding referred to in subsections (a) and (b) of Section 145, or in defense of any claim, issue or matter therein, such person shall be indemnified against expenses (including attorneys’ fees) actually and reasonably incurred by such person in connection therewith; that indemnification provided for by Section 145 shall not be deemed exclusive of any other rights to which the indemnified party may be entitled; and the indemnification provided for by Section 145 shall, unless otherwise provided when authorized or ratified, continue as to a person who has ceased to be a director, officer, employee or agent and shall inure to the benefit of such person’s heirs, executors and administrators. Section 145 also empowers the corporation to purchase and maintain insurance on behalf of any person who is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise against any liability asserted against such person and incurred by such person in any such capacity, or arising out of his status as such, whether or not the corporation would have the power to indemnify such person against such liabilities under Section 145.

Section 102(b)(7) of the DGCL provides that a corporation’s certificate of incorporation may contain a provision eliminating or limiting the personal liability of a director or an officer to the corporation or its stockholders for monetary damages for breach of fiduciary duty as a director or an officer, provided that such provision shall not eliminate or limit the liability of (i) a director or an officer for any breach of the director’s or officer’s duty of loyalty to us or its stockholders, (ii) a director or an officer for any act or omission not in good faith or that involves intentional misconduct or a knowing violation of law; (iii) a director pursuant to Section 174 of the DGCL; (iv) a director or an officer for any transaction from which the director or officer derived an improper personal benefit; or (v) an officer in any action by or in the right of us. Our Restated Certificate provides for this limitation of liability.

Any underwriting agreement or distribution agreement that the registrant enters into with any underwriters or agents involved in the offering or sale of any securities registered hereby may require such underwriters or dealers to indemnify the registrant, some or all of its directors and officers and its controlling persons, if any, for specified liabilities, which may include liabilities under the Securities Act of 1933, as amended.

Our Restated Certificate and Bylaws provide for the indemnification provisions described above and elsewhere herein. We have entered into separate indemnification agreements with our directors and officers which may be broader than the specific indemnification provisions contained in the DGCL. These indemnification agreements generally require us, among other things, to indemnify our officers and directors against liabilities that may arise by reason of their status or service as directors or officers, other than liabilities arising from willful misconduct. These indemnification agreements also generally require us to advance any expenses incurred by the directors or officers as a result of any proceeding against them as to which they could be indemnified. In addition, we have purchased a policy of directors’ and officers’ liability insurance that insures our directors and officers against the cost of defense, settlement or payment of a judgment in some circumstances. These indemnification provisions and the indemnification agreements may be sufficiently broad to permit indemnification of our officers and directors for liabilities, including reimbursement of expenses incurred, arising under the Securities Act of 1933, as amended (the “Securities Act”).

The sales agreement that AN2 Therapeutics has entered into (Exhibit 1.2) provides for indemnification by the sales agent of AN2 Therapeutics, its directors, its officers who sign the registration statement and AN2 Therapeutics’ controlling persons for some liabilities, including liabilities arising under the Securities Act.

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Item 16.

Exhibits

Incorporation by Reference

Exhibit
Number

Exhibit Description

Form

File Number

Exhibit/
Appendix
Reference

Filing

Date

Filed
Herewith

1.1*

Form of Underwriting Agreement

1.2

Open Market Sales Agreement^SM, dated April 9, 2026, between AN2 Therapeutics, Inc. and Jefferies LLC

8-K

001-41331

1.1

4/9/2026

3.1

Amended and Restated Certificate of Incorporation

8-K

001-41331

3.1

6/24/2024

3.2

Amended and Restated Bylaws

S-1

333-263295

3.4

3/4/2022

4.1

Reference is made to Exhibits 3.1 and 3.2

4.2

Form of Specimen Common Stock Certificate

S-1/A

333-263295

4.1

3/21/2022

4.3

Form of Pre-Funded Warrant

8-K

001-41331

4.1

3/10/2026

4.4

Certificate of Designations of Series A Junior Participating Preferred Stock of AN2 Therapeutics, Inc. filed with the Secretary of State of the State of Delaware on August 15, 2024

8-K

001-41331

3.1

8/19/2024

4.5*

Form of Specimen Preferred Stock Certificate

4.6

Form of Indenture

4.7*

Form of Debt Security

4.8*

Form of Warrant

4.9*

Form of Warrant Agreement

4.10*

Form of Unit Agreement

5.1

Opinion of Latham & Watkins LLP

10.1

Securities Purchase Agreement, dated March 8, 2026, by and among the Company and the investors listed therein

8-K

001-41331

10.1

3/10/2026

10.2

Form of Registration Rights Agreement

8-K

001-41331

10.2

3/10/2026

23.1

Consent of Independent Registered Public Accounting Firm

23.2

Consent of Latham & Watkins LLP (See Exhibit 5.1)

24.1

Power of Attorney (See signature page)

25.1*

Statement of Eligibility of Trustee under the Debt Indenture

107

Filing Fee Table

*	To be filed by amendment or as an exhibit to a Current Report on Form 8-K and incorporated herein by reference, if applicable.

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Item 17.

Undertakings

(a) The undersigned registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

(ii) To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the SEC pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

(iii) To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

provided, however, that paragraphs (a)(1)(i), (a)(1)(ii), and (a)(1)(iii) above do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the SEC by the registrant pursuant to section 13 or section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is a part of the registration statement.

(2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(5) That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:

(A) Each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

(B) Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii), or (x) for the purpose of providing the information required by section 10(a) of the Securities Act of 1933 shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or

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prospectus that was part of the registration statement or made in any such document immediately prior to such effective date.

(6) That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities:

The undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

(iv) Any other communications that is an offer in the offering made by the undersigned registrant to the purchaser.

(b) The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(h) Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

(j) The undersigned registrant hereby undertakes to file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act (the “Act”) in accordance with the rules and regulations prescribed by the SEC under section 305(b)(2) of the Act.

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SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Menlo Park, California, on April 9, 2026.


AN2 Therapeutics, Inc.
By:		/s/ Eric Easom
		Eric Easom
		Chief Executive Officer and Director

POWER OF ATTORNEY

Each of the undersigned officers and directors of the registrant hereby severally constitutes and appoints Eric Easom and Lucy O. Day, and each of them singly (with full power to each of them to act alone), as his or her true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution in each of them, for him or her and in his or her name, place and stead, and in any and all capacities, to file and sign any and all amendments, including post-effective amendments, to this registration statement and any other registration statement for the same offering that is to be effective under Rule 462(b) of the Securities Act of 1933, and to file the same, with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith and about the premises as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof. This power of attorney shall be governed by and construed with the laws of the State of Delaware and applicable federal securities laws.

Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed below by the following persons on behalf of the registrant in the capacities and on the dates indicated.


Signature	Title	Date

/s/ Eric Easom Eric Easom	Chief Executive Officer, Chair and Director (Principal Executive Officer)	April 9, 2026

/s/ Lucy O. Day Lucy O. Day	Chief Financial Officer (Principal Financial Officer)	April 9, 2026

/s/ Sarah Williams Sarah Williams	Principal Accounting Officer	April 9, 2026

/s/ Maggie FitzPatrick Maggie FitzPatrick	Lead Independent Director	April 9, 2026

/s/ Kabeer Aziz Kabeer Aziz	Director	April 9, 2026

/s/ Gilbert L. Marks Gilbert L. Marks	Director	April 9, 2026

/s/ Patricia (Patty) Martin Patricia (Patty) Martin	Director	April 9, 2026

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Signature	Title	Date

/s/ Rob Readnour Rob Readnour	Director	April 9, 2026

/s/ Melvin Spigelman Melvin Spigelman	Director	April 9, 2026

/s/ Stephanie Wong Stephanie Wong	Director	April 9, 2026

/s/ Joseph Zakrzewski Joseph Zakrzewski	Director	April 9, 2026

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SEC Form S-3 filed by AN2 Therapeutics Inc.