S-3ASR

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S-3ASR 1 d109006ds3asr.htm S-3ASR S-3ASR

As filed with the Securities and Exchange Commission on May 13, 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

PDF SOLUTIONS, INC.

(Exact name of registrant as specified in its charter)

Delaware

25-1701361

(State or other jurisdiction of

incorporation or organization)

(I.R.S. Employer

Identification Number)

2858 De La Cruz Boulevard

Santa Clara, California 95050

(408) 280-7900

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

John K. Kibarian, Ph.D.

2858 De La Cruz Boulevard

Santa Clara, California 95050

(408) 280-7900

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

Copies to:

Kathleen M. Wells

John C. Williams

Latham & Watkins LLP

801 Jefferson Avenue, Suite 300

Redwood City, California 94063

(650) 328-4600

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. ☐

If 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. ☒

If 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, a 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 the Securities Act. ☐

PROSPECTUS

LOGO

PDF SOLUTIONS, INC.

Common Stock

We may offer and sell, and the selling securityholders may offer and sell, shares of common stock, 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 or any of the selling securityholders offer and sell securities, we or such selling securityholders will provide a supplement to this prospectus, to the extent necessary, that contains specific information about the offering and the amounts, prices and terms of the securities. 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 6 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 “PDFS.” On May 12, 2026, the last reported sale price of our common stock on the Nasdaq Global Select Market was $50.95 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 May 13, 2026.

TABLE OF CONTENTS


ABOUT THIS PROSPECTUS			1
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS			2
WHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE			3
THE COMPANY			5
RISK FACTORS			6
USE OF PROCEEDS			7
DESCRIPTION OF CAPITAL STOCK			8
SELLING SECURITYHOLDERS			12
PLAN OF DISTRIBUTION			13
LEGAL MATTERS			14
EXPERTS			14

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the U.S. Securities and Exchange Commission (the “SEC”) as a “well-known seasoned issuer” as defined in Rule 405 under the Securities Act of 1933, as amended (the “Securities Act”), 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 and the selling securityholders may sell shares of common stock from time to time and 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 “PDF,” “PDF Solutions,” “we,” “our,” “us” and the “Company” in this prospectus, we mean PDF Solutions, Inc. and its consolidated subsidiaries, unless otherwise specified. When we refer to “you,” we mean the potential holders of our common stock.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus, including the documents incorporated or deemed to be incorporated by reference into this prospectus, contains 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”). These statements include, but are not limited to, statements related to: our business strategy and objectives; our intellectual property and proprietary software, information and technology; our sales and marketing strategy, expectations regarding strategic alliances and relationships; investments in research and development; industry trends; macroeconomic factors, inventories, and demand; changing export controls and sanctions; U.S. administrative initiatives; investments in semiconductor manufacturing; geopolitical tensions and conflicts; fluctuations in our quarterly results; and other statements identified by words such as “could,” “expects,” “intends,” “may,” “plans,” “potential,” “should,” “will,” “would,” or similar expressions and the negatives of those terms.

The forward-looking statements contained in this prospectus are based on management’s current beliefs and assumptions and are not guarantees of future performance. The forward-looking statements are subject to various risks, uncertainties, assumptions or changes in circumstances that are difficult to predict or quantify. Actual results may differ materially from these expectations due to numerous factors, many of which are beyond our control, including the risks detailed under “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2025, and as such risk factors may be updated from time to time in our periodic filings with the SEC, which filings are incorporated or deemed to be incorporated by reference into this prospectus and are accessible on the SEC’s website at www.sec.gov. Since it is not possible to foresee all such factors, these factors should not be considered as complete or exhaustive. Consequently, we caution investors not to place undue reliance on any forward-looking statements, as no forward-looking statement can be guaranteed, and actual results may vary materially.

Any forward-looking statements made by us in this prospectus speak only as of the date of this prospectus and are expressly qualified in their entirety by the cautionary statements included in this prospectus. Factors or events that could cause our actual results to differ may emerge from time to time, and it is not possible for us to predict all of them. We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements and you should not place undue reliance on our forward-looking statements. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures, investments or other strategic transactions we may make. Except as required by law, we do not have any obligation to update or revise, or to publicly announce any update or revision to, any of the forward-looking statements, whether as a result of new information, future events or otherwise.

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 www.pdf.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. 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 year ended December 31, 2025, filed with the SEC on February 24, 2026.

•

The information specifically incorporated by reference into our Annual Report on Form 10-K for the year ended December 31, 2025 from our Definitive Proxy Statement on Schedule 14A, filed with the SEC on April 29, 2026.

•

Our Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2026, filed with the SEC on May 7, 2026.

•

Our Current Report on Form 8-K filed with the SEC on April 24, 2026.

•

The description of our Common Stock contained in Exhibit 4.03 to our Annual Report on Form 10-K for the year ended December 31, 2021, filed with the SEC on March 1, 2022 and any amendment or report filed with the SEC for the purpose of updating the description.

All reports and other documents we subsequently file pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act prior to the termination of this offering, 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:

PDF Solutions, Inc.

Attention: Secretary

2858 De La Cruz Boulevard

Santa Clara, California 95050

(408) 280-7900

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 provide comprehensive data solutions designed to empower organizations across the semiconductor and electronics ecosystems to improve the yield and quality of their products and operational efficiency for increased profitability. We derive revenues from two categories, Platform and Volume-based fees. Our offerings that contribute to Platform revenue are licenses for software (other than Cimetrix runtime licenses) and related software maintenance and technical support services; software-as-a-service; engineering services; fixed fees associated with Characterization Vehicle systems; and licenses and purchase contracts for DirectScan systems. Volume-based revenue is derived from Cimetrix runtime licenses, secureWISE data, and variable/royalty fees associated with CV systems (sometimes referred to as Gainshare). Our products and services have been sold to integrated device manufacturers, fabless semiconductor companies, foundries, out-sourced semiconductor assembly and test, capital equipment manufacturers, and system houses.

Corporate Information

Our certificate of incorporation currently in effect is our Third Amended and Restated Certificate of Incorporation, filed with the Secretary of State of the State of Delaware on August 1, 2001, as amended by the Certificate of Amendment thereto filed with the Secretary of State of the State of Delaware on June 20, 2024. Our principal executive offices are located at 2858 De La Cruz Boulevard, Santa Clara, California 95050, and our telephone number at that location is (408) 280-7900. Our website address is www.pdf.com. The information contained on, or that can be accessed through, our website is not incorporated by reference into, and is not part of, this prospectus or the registration statement of which it forms a part, and you should not consider any such information in deciding whether to purchase our securities.

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, operational, 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 occur, our business, financial condition, results of operations or cash flow 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 carefully read the section entitled “Special 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 not complete and may not contain all the information you should consider before investing in our capital stock. This description is summarized from, and qualified in its entirety by reference to, our amended and restated certificate of incorporation and our amended and restated bylaws, each of which has been publicly filed with the SEC. See “Where You Can Find More Information; Incorporation by Reference.”

General

Our authorized capital stock consists of 75,000,000 shares, each with a par value of $0.00015 per share, of which 70,000,000 shares are designated as common stock and 5,000,000 shares are designated as preferred stock. Our shares of capital stock are represented by certificates, unless our board of directors provides by resolution that some or all of any class or series of our stock will be uncertificated. We urge you to read our amended and restated certificate of incorporation and our amended and restated bylaws.

Common Stock

Holders of our common stock are entitled to one vote for each share held on all matters submitted to a vote of stockholders and do not have cumulative voting rights. An election of directors by our stockholders shall be determined by the vote of the majority of the votes cast with respect to that director’s election; provided, that if, as of the 10th day preceding the date on which the Company first mails its notice of meeting for such meeting to stockholders, the Company has received a stockholder’s notice of nominations of persons for election to the board of directors at such meeting, the directors shall be elected by the vote of a plurality of the votes cast at such meeting. Holders of common stock are entitled to receive proportionately any dividends as may be declared by our board of directors, subject to any preferential dividend rights of any series of preferred stock that we may designate and issue in the future.

In the event of our liquidation, dissolution, or winding up, the holders of common stock are entitled to receive proportionately our net assets available for distribution to stockholders after the payment in full of all debts and other liabilities and subject to the prior rights of any outstanding preferred stock. Holders of common stock have no preemptive, subscription, redemption or conversion rights. There are no sinking fund provisions applicable to our common stock. The rights, preferences and privileges of holders of common stock are subject to and may be adversely affected by the rights of the holders of shares of any series of preferred stock that we may designate and issue in the future.

Preferred Stock

Under the terms of our amended and restated certificate of incorporation, our board of directors is authorized to direct us to issue shares of preferred stock in one or more series without stockholder approval. Our board of directors has the discretion to determine the rights, preferences, privileges and restrictions, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences, of each series of preferred stock.

Authorized but Unissued Shares

The authorized but unissued shares of our common stock and our preferred stock are available for future issuance without stockholder approval, subject to any limitations imposed by the listing standards of The Nasdaq Stock Market LLC.

Anti-Takeover Effects of Provisions of Our Amended and Restated Certificate of Incorporation, Our Amended and Restated Bylaws and Delaware Law

Provisions in our amended and restated certificate of incorporation and our amended and restated bylaws, as well as provisions of the Delaware General Corporation Law (the “DGCL”), could make it more difficult for a third party to acquire us or increase the cost of acquiring us, even if doing so would benefit our stockholders, including transactions in which stockholders might otherwise receive a premium for their shares.

Classified Board of Directors

Our amended and restated certificate of incorporation provides that the board of directors is divided into three classes, designated Class I, Class II and Class III, as nearly equal in number as reasonably possible, with each class serving a three-year staggered term. As a result, approximately one-third of our directors are elected each year. Each director shall serve until his or her successor is duly elected and qualified or until his or her death, resignation or removal. Any director, or the entire board of directors, may be removed from office, with or without cause, by the holders of a majority of the voting power of the then-outstanding shares of our voting stock entitled to vote generally in the election of directors, voting together as a single class. Any vacancies on the board of directors resulting from death, resignation, disqualification, removal or other causes may be filled by either (i) the affirmative vote of the holders of a majority of the voting power of the then-outstanding shares of voting stock, voting together as a single class, or (ii) the affirmative vote of a majority of the remaining directors then in office, even though less than a quorum of the board of directors. Subject to the rights of any series of preferred stock then outstanding, newly created directorships resulting from any increase in the number of directors shall, unless the board of directors determines that any such newly created directorship shall be filled by the stockholders, be filled only by the affirmative vote of the directors then in office, even though less than a quorum, or by a sole remaining director.

Special Meetings of Stockholders

Our amended and restated bylaws provide that a special meeting of the stockholders may be called at any time by the board of directors, by the chairperson of the board, or by the president. Our amended and restated bylaws require that the notice for a special meeting specify the purpose or purposes for which the meeting is called, and business at any special meeting is limited to the purpose or purposes stated in the notice.

Stockholder Action by Written Consent

Pursuant to Section 228 of the DGCL, any action required to be taken at any annual or special meeting of the stockholders may be taken without a meeting, without prior notice and without a vote if a consent or consents in writing, setting forth the action so taken, is signed by the holders of outstanding stock having not less than the minimum number of votes that would be necessary to authorize or take such action at a meeting at which all shares of our stock entitled to vote thereon were present and voted, unless our amended and restated certificate of incorporation provides otherwise. Our amended and restated certificate of incorporation provides that no action shall be taken by the stockholders other than at an annual or special meeting of the stockholders, upon due notice and in accordance with the provisions of our bylaws, and no action shall be taken by the stockholders by written consent. Accordingly, stockholder action by written consent is prohibited.

Requirements for Advance Notification of Stockholder Meetings, Nominations and Proposals

Our amended and restated bylaws require that any stockholder who wishes to bring business before an annual meeting or nominate directors must comply with the advance notice requirements set forth therein. In addition, our amended and restated bylaws contain a proxy access provision that, subject to specified eligibility, ownership, procedural and disclosure requirements, permits an eligible stockholder, or a group of up to 20 eligible stockholders, that has owned at least 5% of our outstanding common stock continuously for at least three years to include in our proxy materials for an annual meeting of stockholders director nominees constituting up to the greater of two or 20% of our board of directors.

Approval for Amendment of Certificate of Incorporation and Bylaws

The DGCL provides generally that the affirmative vote of holders of a majority in voting power of outstanding shares entitled to vote on the matter is required to amend a corporation’s certificate of incorporation, unless a corporation’s certificate of incorporation requires a greater percentage. Our amended and restated certificate of incorporation provides that the affirmative vote of holders of at least 66 2/3% of the voting power of all of the then-outstanding shares of our voting stock entitled to vote is required to amend or adopt our bylaws by stockholder action. The board of directors is also expressly authorized to adopt, amend or repeal our bylaws. Our amended and restated certificate of incorporation reserves the right to amend, alter, change or repeal any provision contained therein, in the manner now or hereafter prescribed by statute, and all rights conferred upon stockholders therein are granted subject to this reservation.

Business Combinations

We are subject to Section 203 of the DGCL, which generally prohibits a Delaware corporation from engaging in any business combination (as defined in Section 203) with any interested stockholder (as defined in Section 203) for a period of three years following the time that such stockholder became an interested stockholder, unless (i) prior to such time, the board of directors approved either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder, (ii) upon consummation of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of our voting stock outstanding at the time the transaction commenced (excluding specified shares) or (iii) at or subsequent to such time, the business combination is approved by the board of directors and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least 66 2/3% of our outstanding voting stock that is not owned by the interested stockholder.

Exclusive Venue

Our amended and restated bylaws provide that, unless we consent in writing to the selection of an alternative forum, the Court of Chancery in the State of Delaware shall be the sole and exclusive forum for (i) any derivative action or proceeding brought on our behalf, (ii) any action asserting a claim of breach of a fiduciary duty owed by any current or former director, officer, stockholder, employee or agent of the Company to us or our stockholders, including a claim alleging the aiding and abetting of such a breach of fiduciary duty, (iii) any action asserting a claim against us or any current or former director, officer, stockholder, employee or agent of the Company arising out of or relating to any provision of the DGCL, our amended and restated certificate of incorporation or our amended and restated bylaws, (iv) any action asserting a claim related to or involving the Company or any director, officer, stockholder, employee or agent of the Company that is governed by the internal affairs doctrine of the State of Delaware, or (v) any action asserting an “internal corporate claim” as that term is defined in Section 115 of the DGCL; provided, however, that, in the event that the Court of Chancery lacks subject matter jurisdiction over any such action or proceeding, the sole and exclusive forum for such action or proceeding shall be another state or federal court located within the State of Delaware. The Delaware exclusive forum provision described above does not apply to any suits brought to enforce any liability or duty created by the Exchange Act, the Securities Act or any other claim for which the federal courts of the United States have exclusive jurisdiction. Any person or entity purchasing or otherwise acquiring any interest in our shares of capital stock will be deemed to have notice of and consented to the foregoing forum selection provisions. Although our amended and restated bylaws contain the exclusive forum provisions described above, it is possible that a court could find that such provisions are inapplicable for a particular claim or action or that such provisions are unenforceable.

Limitation of Liability and Indemnification

Our amended and restated certificate of incorporation provides that, to the fullest extent permitted by the DGCL, as the same may be amended from time to time, no director or officer of the Company shall be personally

liable to us or our stockholders for monetary damages for breach of fiduciary duty as a director or officer. If the DGCL is hereafter amended to authorize corporate action further limiting or eliminating the personal liability of directors or officers, then the liability of our directors and officers will be limited or eliminated to the fullest extent permitted by the DGCL, as so amended. Our amended and restated certificate of incorporation also authorizes us, to the fullest extent permitted by applicable law, to provide indemnification of (and advancement of expenses to) our agents and other persons through bylaw provisions, agreements with such persons, vote of stockholders or disinterested directors or otherwise, in excess of the indemnification and advancement otherwise permitted by Section 145 of the DGCL.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare Trust Company, N.A.

Stock Exchange Listing

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

SELLING SECURITYHOLDERS

Information about selling securityholders, where applicable, will be set forth in a prospectus supplement, in a post-effective amendment or in filings we make with the SEC under the Exchange Act that are incorporated by reference.

PLAN OF DISTRIBUTION

We or any of the selling securityholders may sell the offered securities from time to time:

•

through underwriters or dealers;

•

through agents;

•

directly to one or more purchasers; or

•

through a combination of any of these methods of sale.

We will identify the specific plan of distribution, including any underwriters, dealers, agents or direct purchasers and their compensation in the applicable prospectus supplement.

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 PDF Solutions, 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 consolidated financial statements of PDF Solutions, Inc. as of December 31, 2025 and 2024 and for each of the three years in the period ended December 31, 2025, and management’s assessment of the effectiveness of internal control over financial reporting (which is included in Management’s Report on Internal Control over Financial Reporting) as of December 31, 2025, incorporated in this Registration Statement on Form S-3 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 reports of BPM LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

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)
FINRA filing fee	$	(2)
The Nasdaq Global Select Market listing 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)
Miscellaneous	$	(2)

Total	$	(1)(2)

(1)	Pursuant to Rules 456(b) and 457(r) under the Securities Act, the SEC registration fee will be paid at the time of any particular offering of securities under the registration statement, and is therefore not currently determinable.

(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

Our amended and restated certificate of incorporation authorizes us to provide indemnification to the fullest extent permitted by applicable law, and our amended and restated bylaws provide that we will indemnify our directors and officers to the maximum extent permitted by the DGCL. Subsection (a) of Section 145 of 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 such person’s 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 officer to the corporation or its stockholders for monetary damages for breach of fiduciary duty as a director or officer, provided that such provision shall not eliminate or limit the liability of (i) a director or officer for any breach of the director’s or officer’s duty of loyalty to the corporation or its stockholders, (ii) a director or officer for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (iii) a director under Section 174 of the DGCL, (iv) a director or 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 the corporation. Our amended and restated certificate of incorporation contains a provision which eliminates directors’ and officers’ personal liability as set forth above.

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.

We have in effect insurance policies for general officers’ and directors’ liability insurance covering all of our officers and directors. In addition, we have entered into indemnification agreements with certain of our directors and officers. These indemnification agreements may require us, among other things, to indemnify each such director or officer for certain expenses, including attorneys’ fees, judgments, fines and settlement amounts incurred by such director or officer in any action or proceeding arising out of such person’s service as one of our directors or officers.

Item 16.

Exhibits


Exhibit Number		Description

1.1*		Form of Underwriting Agreement.

3.1		Third Amended and Restated Certificate of Incorporation of PDF Solutions, Inc., and Certificate of Amendment to Third Amended and Restated Certificate of Incorporation of PDF Solutions, Inc. (incorporated by reference to Exhibit 3.01 to the Company’s Quarterly Report on Form 10-Q filed with the SEC on August 8, 2024).

3.2		Amended and Restated Bylaws of PDF Solutions, Inc. (incorporated by reference to Exhibit 3.1 to the Company’s Current Report on Form 8-K filed with the SEC on May 1, 2019).

5.1		Opinion of Latham & Watkins LLP.

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Exhibit Number		Description

23.1		Consent of Latham & Watkins LLP (included in Exhibit 5.1).

23.2		Consent of BPM LLP, independent registered public accounting firm.

24.1		Powers of Attorney (incorporated by reference to the signature page hereto).

107		Filing Fee Table.

*	To be filed by amendment or incorporated by reference in connection with the offering of the securities.

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;

(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; 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 Commission by the registrant pursuant to section 13 or section 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), 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, 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 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 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

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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 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 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 communication 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, each filing of the registrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to section 15(d) of the Exchange Act) 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 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 Securities and Exchange Commission 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.

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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 Santa Clara, California, on May 13, 2026.


PDF Solutions, Inc.

By:		/s/ John K. Kibarian
Name:		John K. Kibarian
Title:		President and Chief Executive Officer

POWER OF ATTORNEY

Each of the undersigned officers and directors of the registrant hereby severally constitutes and appoints John K. Kibarian and Adnan Raza, 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, as amended, 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 in accordance 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/ John K. Kibarian John K. Kibarian	Director, President and Chief Executive Officer (Principal executive officer)	May 13, 2026

/s/ Adnan Raza Adnan Raza	Executive Vice President, Finance and Chief Financial Officer (Principal financial and accounting officer)	May 13, 2026

/s/ Joseph R. Bronson Joseph R. Bronson	Lead Independent Director	May 13, 2026

/s/ Chi-Foon Chan Chi-Foon Chan	Director	May 13, 2026

/s/ Nancy Erba Nancy Erba	Director	May 13, 2026

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Signature	Title	Date

/s/ Michael Gustafson Michael Gustafson	Director	May 13, 2026

/s/ Ye Jane Li Ye Jane Li	Director	May 13, 2026

/s/ Kimon Michaels Kimon Michaels	Director	May 13, 2026

/s/ Shuo Zhang. Shuo Zhang	Director	May 13, 2026

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Large accelerated filer

Accelerated filer

Non-accelerated filer

Smaller reporting company

Emerging growth company

SEC Form S-3ASR filed by PDF Solutions Inc.