DENISON MINES CORP._December 31, 2025

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 40-F

(Check One)

☐	Registration statement pursuant to Section 12 of the Securities Exchange Act of 1934

☒	Annual report pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934

For the fiscal year ended: December 31, 2025

Commission file number: 001-33414

DENISON MINES CORP.

(Exact name of registrant as specified in its charter)

Ontario, Canada

(Province or other jurisdiction of incorporation or organization)

1090

(Primary standard industrial classification code number)

98-0622284

(I.R.S. employer identification number)

1100 – 40 University Avenue
Toronto, Ontario M5J 1T1 Canada
416-979-1991

(Address and telephone number of registrant’s principal executive offices)

C T Corporation System

28 Liberty Street

New York, NY 10005

Phone number: 212-894-8940

(Name, address and telephone number of agent for service in the United States)

Securities registered pursuant to Section 12(b) of the Securities Exchange Act of 1934 (“Exchange Act”):

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Shares		DNN		NYSE American LLC

Securities registered pursuant to Section 12(g) of the Exchange Act: None

Securities for which there is a reporting obligation pursuant to Section 15(d) of the Exchange Act: Not applicable.

For annual reports, indicate by check mark the information filed with this form:

☒ Annual Information Form

☒ Audited Annual Financial Statements

Indicate the number of outstanding shares of each of the issuer’s classes of capital or common stock as of the close of the period covered by the annual report: 901,610,950 Common Shares as of December 31, 2025.

Indicate by check mark whether the registrant: (1) has filed all reports required to be filed by Section 13(d) or 15(d) of the Exchange Act during the preceding 12 months (or for such shorter period that the registrant has been required to file such reports); and (2) has been subject to such filing requirements in the past 90 days.

Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).

Yes ☒ No ☐

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 12b-2 of the Exchange Act.

Emerging growth company ☐

If an emerging growth company that prepares its financial statements in accordance with U.S. GAAP, 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 13(a) of the Exchange Act. ☐

† The term “new or revised financial accounting standard” refers to any update issued by the Financial Accounting Standards Board to its Accounting Standards Codification after April 5, 2012.

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☒

If securities are registered pursuant to Section 12(b) of the Exchange Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

EXPLANATORY NOTE

Denison Mines Corp. (the “Company” or the “Registrant”) is an Ontario corporation eligible to file its Annual Report pursuant to Section 13(a) of the United States Securities Exchange Act of 1934, as amended (the “Exchange Act”), on Form 40-F. The Registrant is a “foreign private issuer” as defined in Rule 3b-4 under the Exchange Act. Equity securities of the Registrant are accordingly exempt from Sections 14(a), 14(b), 14(c), 14(f) and 16(b) and 16(c) of the Exchange Act pursuant to Rule 3a12-3 thereunder.

DOCUMENTS FILED PURSUANT TO GENERAL INSTRUCTIONS

In accordance with General Instruction B.(3) of Form 40-F, the Registrant hereby incorporates by reference Exhibits 99.1 through 99.3 as set forth in the Exhibit Index attached hereto, which are deemed filed herewith.

In accordance with General Instruction D.(9) of Form 40-F, the Registrant has filed written consents of certain experts named in the foregoing Exhibits as Exhibits 99.4 and 99.9 through 99.28, as set forth in the Exhibit Index attached hereto.

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

Certain of the information contained in this Annual Report on Form 40-F, including the documents incorporated herein by reference, may contain “forward-looking information” and “forward-looking statements” within the meaning of applicable Canadian and U.S. securities laws. Forward-looking information and statements may include, among others, statements regarding the future plans, costs, objectives or performance of the Company, or the assumptions underlying any of the foregoing. In this Annual Report on Form 40-F, words such as “may”, “would”, “could”, “will”, “likely”, “believe”, “expect”, “anticipate”, “intend”, “plan”, “estimate” and similar words and the negative form thereof are used to identify forward-looking statements. Forward-looking statements should not be read as guarantees of future performance or results, and will not necessarily be accurate indications of whether, or the times at or by which, such future performance will be achieved. Forward-looking statements and information are based on information available at the time and/or management’s good-faith belief with respect to future events and are subject to known or unknown risks, uncertainties and other unpredictable factors, many of which are beyond the Company’s control. These risks, uncertainties and assumptions include, but are not limited to, those described under the section “Risk Factors” in the Company’s Annual Information Form for the fiscal year ended December 31, 2025 (the “AIF”), which is filed as Exhibit 99.1 to this Annual Report on Form 40-F, and could cause actual events or results to differ materially from those projected in any forward-looking statements.

The Company’s forward-looking statements contained in the exhibits incorporated by reference into this Annual Report on Form 40-F are made as of the respective dates set forth in such exhibits. In preparing this Annual Report on Form 40-F, the Company has not updated such forward-looking statements to reflect any subsequent information, events or circumstances or otherwise, or any change in management’s beliefs, expectations or opinions that may have occurred prior to the date hereof, nor does the Company assume any obligation to update such forward-looking statements in the future, except as required by applicable laws.

NOTE TO UNITED STATES READERS – DIFFERENCES IN UNITED STATES AND CANADIAN REPORTING PRACTICES

The Registrant is permitted, under a multijurisdictional disclosure system adopted by the United States, to prepare this Annual Report on Form 40-F in accordance with Canadian disclosure requirements, which are different from those of the United States.

The Registrant prepares its consolidated financial statements, which are filed with this Annual Report on Form 40-F, in accordance with International Financial Reporting Standards, as issued by the International Accounting Standards Board (“IFRS”). IFRS differs in some significant respects from United States generally accepted accounting principles (“U.S. GAAP”), and thus the Registrant’s financial statements may not be comparable to the financial statements of United States companies. These differences between IFRS and U.S. GAAP might be material to the financial information presented in this Annual Report on Form 40-F. In addition, differences may arise in subsequent periods related to changes in IFRS or U.S. GAAP or due to new transactions that the Registrant enters into. The Registrant is not required to prepare a reconciliation of its consolidated financial statements and related footnote disclosures between IFRS and U.S. GAAP and has not quantified such differences.

CURRENCY

Unless otherwise indicated, all dollar amounts in this Annual Report on Form 40-F are in Canadian dollars. The daily exchange rate published by the Bank of Canada for the exchange of Canadian dollars into United States dollars on December 31, 2025 was CDN$1.00 = U.S.$0.7296. The daily exchange rate published by the Bank of Canada for the exchange of Canadian dollars into United States dollars on December 31, 2024 was CDN$1.00 = U.S.$0.6950.

DISCLOSURE CONTROLS AND PROCEDURES AND

INTERNAL CONTROL OVER FINANCIAL REPORTING

A.Disclosure Controls and Procedures

The Company maintains disclosure controls and procedures to ensure that information required to be disclosed in the Company’s filings under the Exchange Act, is recorded, processed, summarized and reported in accordance with the requirements specified in the rules and forms of the SEC. The Company carried out an evaluation, under the supervision and with the participation of its management, including the Chief Executive Officer and Chief Financial Officer, of the effectiveness of the design and operation of the Company’s “disclosure controls and procedures” (as defined in Rule 13a-15(e) or Rule 15d-15(e) under the Exchange Act) as of the end of the period covered by this Annual Report on Form 40-F. Based upon that evaluation, the Chief Executive Officer and Chief Financial Officer concluded that the Company’s disclosure controls and procedures as of December 31, 2025 were effective to ensure that information required to be disclosed by the Registrant in reports it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms and is accumulated and communicated to the Registrant’s management, including its Chief Executive Officer and Chief Financial Officer, as appropriate to allow timely decisions regarding required disclosure.

The Company’s disclosure controls and procedures are designed to provide reasonable assurance of achieving their objectives and, as indicated in the preceding paragraph, the Chief Executive Officer and Chief Financial Officer believe that the Company’s disclosure controls and procedures are effective at that reasonable assurance level, although the Chief Executive Officer and Chief Financial Officer do not expect that the disclosure controls and procedures will prevent or detect all errors and all fraud.

It should be noted that a control system, no matter how well conceived or operated, can provide only reasonable, not absolute, assurance that the objectives of the control system are met. The Company will continue to periodically review its disclosure controls and procedures and may make such modifications from time to time as it considers necessary.

B.Management’s Annual Report on Internal Control Over Financial Reporting

The Company’s management, including the Chief Executive Officer and Chief Financial Officer, is responsible for establishing and maintaining adequate internal control over the Company’s financial reporting (as defined in Rules 13a-15(f) or 15d-15(f) under the Exchange Act). Internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of the Company’s financial reporting and the preparation of financial statements for external purposes in accordance with IFRS.

A company’s internal control over financial reporting includes those policies and procedures that (i) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (ii) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (iii) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Management, including the Chief Executive Officer and Chief Financial Officer, conducted an assessment of the Company’s internal control over financial reporting based on the framework established by the Committee of Sponsoring Organizations of the Treadway Commission on Internal Control — Integrated Framework (2013). Based on this assessment, management concluded that, as of December 31, 2025, the Company’s internal control over financial reporting is effective.

It should be noted that a control system, no matter how well conceived or operated, can only provide reasonable, not absolute, assurance that the objectives of the control system are met. The Company will continue to periodically review its internal control over financial reporting and may make such modifications from time to time as it considers necessary.

C.Attestation Report of the Independent Registered Public Accounting Firm

The effectiveness of the Registrant’s internal control over financial reporting as of December 31, 2025 has been audited by KPMG LLP, an Independent Registered Public Accounting Firm, as stated in their report included with the Registrant’s Audited Financial Statements, which are incorporated by reference as Exhibit 99.3 to this Annual Report on Form 40-F.

D.Changes in Internal Control Over Financial Reporting

There were no changes in the Company’s internal control over financial reporting during the twelve months ended December 31, 2025 that have materially affected, or are reasonably likely to materially affect, the Company’s internal control over financial reporting.

NOTICES PURSUANT TO REGULATION BTR

There were no notices required by Rule 104 of Regulation BTR during the fiscal year ended December 31, 2025, concerning any equity security subject to a blackout period under Rule 101 of Regulation BTR.

AUDIT COMMITTEE FINANCIAL EXPERT AND AUDIT COMMITTEE QUALIFICATIONS

The Company’s Board of Directors has determined that each of Ms. Patricia Volker, Chair of the Audit Committee, and Mr. Ken Hartwick are audit committee financial experts within the meaning of paragraph 8(b) of General Instruction B of Form 40-F, and that all three members of the Audit Committee (Ms. Patricia Volker, Mr. Ken Hartwick and Mr. David Neuburger) are independent within the meaning of United States and Canadian securities regulations and applicable stock exchange requirements.

The SEC has provided that the designation of an audit committee financial expert does not make him or her an “expert” for any purpose, impose on him or her any duties, obligations or liability that are greater than the duties, obligations or liability imposed on him or her as a member of the Audit Committee and the Board in the absence of such designation, or affect the duties, obligations or liability of any other member of the Audit Committee or Board.

CODE OF ETHICS

The Company has adopted a code of ethics that applies to the Company’s directors, officers and employees, including the Chief Executive Officer, the Chief Financial Officer, the principal accounting officer or controller, persons performing similar functions and other officers, directors and employees of the Company. A current copy of the code of ethics is on the Company’s website at www.denisonmines.com. In the fiscal year ended December 31, 2025, the Company has not made any amendment to a provision of its code of ethics that applies to any of its Chief Executive Officer, Chief Financial Officer, principal accounting officer or controller or persons performing similar functions that relates to one or more of the items set forth in paragraph (9)(b) of General Instruction B to Form 40-F. In the fiscal year ended December 31, 2025, the Company has not granted a waiver (including an implicit waiver) from a provision of its code of ethics to any of its Chief Executive Officer, Chief Financial Officer, principal accounting officer or controller or persons performing similar functions that relates to one or more of the items set forth in paragraph (9)(b) of General Instruction B to Form 40-F.

Unless and to the extent specifically referred to herein, the information on the Company’s website shall not be deemed to be incorporated by reference in this Annual Report. Except for the code of ethics, and notwithstanding references to the Company’s website or other websites in the AIF or in the documents incorporated by reference herein or attached as exhibits hereto, no information contained on the Company’s website or any other website shall be incorporated by reference in this Annual Report or in the documents incorporated by reference herein or attached as Exhibits hereto.

PRINCIPAL ACCOUNTANT FEES AND SERVICES

KPMG LLP, Toronto, ON, Canada (Auditor Firm ID: 85), acted as the Company’s independent registered public accounting firm for the fiscal year ended December 31, 2025.

See the section “Denison’s Governance – Standing Committees of the Board – Audit Committee” in the AIF, which section is incorporated by reference herein, for the total fees billed to the Company by KPMG LLP during last two fiscal years by category of service (for audit fees, audit-related fees, tax fees and all other fees).

AUDIT COMMITTEE PRE-APPROVAL POLICIES AND PROCEDURES

The Company’s Audit Committee mandate and charter provides that the Audit Committee shall (i) approve, prior to the auditor’s audit, the auditor’s audit plan (including, without limitation, staffing), the scope of the auditor’s review and all related fees, and (ii) pre-approve any non-audit services (including, without limitation, fees therefor) provided to the Company or its subsidiaries by the auditor or any auditor of any such subsidiary and shall consider whether these services are compatible with the auditor’s independence, including, without limitation, the nature and scope of the specific non-audit services to be performed and whether the audit process would require the auditor to review any advice rendered by the auditor in connection with the provision of non-audit services.

The following sets forth the percentage of services described above that were approved by the audit committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X:


	2025		2024
Audit Related Fees:	100	%	100	%
Tax Fees:	100	%	100	%
All Other Fees:	100	%	100	%

OFF-BALANCE SHEET ARRANGEMENTS

The Company has no off-balance sheet arrangements that have, or are reasonably likely to have, a material effect on the Company’s financial condition, changes in financial condition, revenues or expenses, results of operations, liquidity, cash requirements or capital resources.

IDENTIFICATION OF THE AUDIT COMMITTEE

The Company has a separately-designated standing audit committee established in accordance with Section 3(a)(58)(A) of the Exchange Act. The committee members now, and for the financial year ended December 31, 2025, are Ms. Patricia Volker (Chair), Mr. Ken Hartwick and Mr. David Neuburger. For further information on these members, see “Audit Committee Financial Expert” above.

CORPORATE GOVERNANCE PRACTICES

The Company’s common shares are listed on the NYSE American. Section 110 of the NYSE American Company Guide permits the NYSE American to consider the laws, customs and practices of foreign issuers in relaxing certain NYSE American listing criteria, and to grant exemptions from the NYSE American listing criteria based on these considerations. An issuer seeking relief under these provisions is required to provide written certification from independent local counsel that the non-complying practice is not prohibited by home country law. A description of the significant ways in which the Company’s governance practices differ from those followed by domestic companies pursuant to the NYSE American standards is as follows:

Shareholder Meeting Quorum Requirement: The NYSE American minimum quorum requirement for a shareholder meeting is one-third of the shares issued and outstanding and entitled to vote for a meeting of a listed company’s shareholders. The TSX does not specify a quorum requirement for a meeting of a listed company’s shareholders. The Company’s current required quorum at any meeting of shareholders as set forth in the Company’s by-laws is two persons present, each being a shareholder entitled to vote at the meeting or a duly appointed proxyholder for an absent shareholder so entitled, holding or representing in aggregate not less than 10% of the shares of the Company entitled to be voted at the meeting. The Company’s current quorum requirement is not prohibited by, and does not constitute a breach of, the Business Corporations Act (Ontario) (the “OBCA”), applicable Canadian securities laws or the rules and policies of the TSX.

Proxy Solicitation Requirement: The NYSE American requires the solicitation of proxies and delivery of proxy statements for all shareholder meetings of a listed company, and requires that these proxies be solicited pursuant to a proxy statement that conforms to the proxy rules of the U.S. Securities and Exchange Commission. The Company is a foreign private issuer as defined in Rule 3b-4 under the Exchange Act, and the equity securities of the Company are accordingly exempt from the proxy rules set forth in Sections 14(a), 14(b), 14(c) and 14(f) of the Exchange Act. The Company solicits proxies in accordance with the OBCA, applicable Canadian securities laws and the rules and policies of the TSX.

Shareholder Approval Requirements: The NYSE American requires a listed company to obtain the approval of its shareholders for certain types of securities issuances. One is the sale of common shares (or securities convertible into common shares) at a discount to officers or directors. The TSX rules require shareholder approval for the issuance of shares to insiders in private placements where insiders are being issued more than 10% of the presently issued and outstanding shares. The NYSE American also requires shareholder approval of private placements that may result in the issuance of common shares (or securities convertible into common shares) equal to 20% or more of presently outstanding shares for less than a prescribed minimum price based on recent closing prices. There is no such requirement under Ontario law. The TSX rules require shareholder approval for private placements that materially affect control, or where more than 25% of presently issued and outstanding shares will be issued at a discount to market. The Company will seek a waiver from the NYSE American shareholder approval requirement should a dilutive securities issuance trigger such NYSE American shareholder approval requirement in circumstances where such securities issuance does not trigger a shareholder approval requirement under the rules of the TSX.

The foregoing are consistent with the laws, customs and practices in Canada.

In addition, the Company may from time-to-time seek relief from the NYSE American corporate governance requirements on specific transactions under Section 110 of the NYSE American Company Guide by providing written certification from independent local counsel that the non-complying practice is not prohibited by its home country law, in which case, the Company shall make the disclosure of such transactions available on its website at www.denisonmines.com. Information contained on, or accessible through, our website is not part of this Annual Report on Form 40-F.

MINE SAFETY DISCLOSURE

Not applicable.

UNDERTAKING AND CONSENT TO SERVICE OF PROCESS

A.Undertaking

The Company undertakes to make available, in person or by telephone, representatives to respond to inquiries made by the Commission staff, and to furnish promptly, when requested to do so by the Commission staff, information relating to: the securities registered pursuant to Form 40-F; the securities in relation to which the obligation to file an Annual Report on Form 40-F arises; or transactions in said securities.

B.Consent to Service of Process

The Company has previously filed with the SEC a Form F-X in connection with its common shares. Any change to the name or address of the Company’s agent for service shall be communicated promptly to the SEC by amendment to the Form F-X referencing the file number of the Company.

SIGNATURES

Pursuant to the requirements of the Exchange Act, the Company certifies that it meets all of the requirements for filing on Form 40-F and has duly caused this Annual Report on Form 40-F to be signed on its behalf by the undersigned, thereto duly authorized.


Registrant: DENISON MINES CORP.

By:	/s/ David D. Cates

Title:	President and Chief Executive Officer

Date:	March 30, 2026

EXHIBIT INDEX


97.1		Policy Relating to Recovery of Erroneously Awarded Compensation (incorporated by reference to Exhibit 97.1 of the Registrant’s Annual Report on Form 40-F furnished to the Commission on March 28, 2024)

99.1		Annual Information Form for the Year Ended December 31, 2025

99.2		Management’s Discussion and Analysis of Results of Operations and Financial Condition for the Year ended December 31, 2025

99.3		Consolidated Audited Financial Statements for the Years Ended December 31, 2025 and 2024 together with Management’s Report on Internal Control over Financial Reporting and the report of our Independent Registered Public Accounting Firm thereon

99.4		Consent of KPMG LLP

99.5		Certificate of Chief Executive Officer as required by Rule 13a-14(a) or Rule 15d-14(a), pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

99.6		Certificate of Chief Financial Officer as required by Rule 13a-14(a) or Rule 15d-14(a), pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

99.7		Certificate of Chief Executive Officer pursuant to 18 U.S.C. Section 1350, as enacted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002

99.8		Certificate of Chief Financial Officer pursuant to 18 U.S.C. Section 1350, as enacted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002

99.9		Consent of Chad Sorba, P.Geo.

99.10		Consent of SRK Consulting (Canada) Inc.

99.11		Engcomp Engineering and Computing Professionals Inc.

99.12		Consent of Gordon Graham, P.Eng.

99.13		Consent of Stantec Consulting Ltd.

99.14		Consent of Mark Hatton, P. Eng.

99.15		Consent of SLR Consulting (Canada) Ltd.

99.16		Consent of Mark Mathisen C.P.G.

99.17		Consent of Wood Canada Limited

99.18		Consent of David Myers, P. Eng.

99.19		Consent of Lorne Schwartz, P. Eng.

99.20		Consent of Dan Johnson, P.E., RM SME

99.21		Consent of Newmans Geotechnique Inc.

99.22		Consent of Gregory Newman, P. Eng.

99.23		Consent of Egis Canada Ltd.

99.24		Consent of Jeffery Martin, P.Eng.

99.25		Consent of Hatch Ltd.

99.26		Consent of William McCombe, P.Eng.

99.27		Consent of CanCost Consulting

99.28		Consent of Geoffrey Wilkie, P. Eng.

101		Interactive Data File (formatted as Inline XBRL)

104		Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)

SEC Form 40-F filed by Denison Mines Corp