An anonymous director reports

DENISON COMPLETES US$55 MILLION OFFERING TO FUND LONG-LEAD PROCUREMENT FOR PHOENIX ISR PROJECT

Denison Mines Corp. has closed the previously announced bought deal public offering of common shares, resulting in the issuance of 37 million shares, at a price of $1.49 (U.S.) per share, for total gross proceeds of $55.13-million (U.S.).

The offering was completed through a syndicate of underwriters led by Cantor Fitzgerald Canada Corp., as sole bookrunner and lead underwriter, together with Canaccord Genuity Corp., Haywood Securities Inc., Raymond James Ltd., BMO Nesbitt Burns Inc., Scotia Capital Inc., Cormark Securities Inc. and SCP Resource Finance LP, pursuant to an underwriting agreement between Denison and the underwriters dated Oct. 11, 2023.

Denison intends to use the net proceeds from the offering to finance: (1) the advancement of the proposed Phoenix in situ recovery uranium mining operation through the procurement of long-lead items (including associated engineering, testing and design) identified during the continuing front-end engineering design process and the Phoenix feasibility study; (2) exploration and evaluation expenditures; and (3) general corporate and administrative expenses, including those in support of corporate development activities, and working capital requirements.

Based upon preliminary budgets and plans, Denison expects the funds, taken together with existing financial resources, including those from prior prospectus financings, will be sufficient to advance the Phoenix project to a final investment decision and into the project execution phase. Denison further expects to be able to finance operations during this period while maintaining a large portion of its current physical uranium holdings, which are planned to be utilized in the future in connection with financing the continued advancement and/or construction of the Phoenix project.

The common shares were qualified for issuance pursuant to a prospectus supplement to the company's existing Canadian short form base shelf prospectus and U.S. registration statement on Form F-10, as amended (file No. 333-258939), each dated Sept. 16, 2021. The registration statement was declared effective by the United States Securities and Exchange Commission (SEC) on Sept. 17, 2021. The prospectus supplement has been filed with the securities commissions in each of the provinces and territories of Canada, except Quebec, and with the SEC. The Canadian prospectus supplement is available on SEDAR+ maintained by the Canadian Securities Administrators. The U.S. prospectus supplement (together with the related U.S. base shelf prospectus) is available on the SEC's website. Alternatively, the prospectus supplement may be obtained upon request by contacting the company or Cantor Fitzgerald Canada Corp. in Canada, attention: Equity Capital Markets, 181 University Ave., Suite 1500, Toronto, Ont., M5H 3M7, or by e-mail at ecmcanada@cantor.com, or Cantor Fitzgerald & Co., attention: equity capital markets, 499 Park Ave., on the sixth floor, New York, N.Y., 10022, or by e-mail at prospectus@cantor.com.

About Wheeler River Corp.

Wheeler River is the largest undeveloped uranium project in the infrastructure-rich eastern portion of the Athabasca basin region in Northern Saskatchewan. The project is host to the high-grade Phoenix and Gryphon uranium deposits, discovered by Denison in 2008 and 2014, respectively, and is a joint venture between Denison (90 per cent and operator) and JCU (Canada) Exploration Company Ltd. (10 per cent). In August, 2023, Denison filed a technical report summarizing the results of: (1) the feasibility study completed for in situ recovery (ISR) mining of the high-grade Phoenix uranium deposit; and (2) a cost update to the 2018 prefeasibility study for conventional underground mining of the basement-hosted Gryphon uranium deposit. Based on the respective studies, both deposits have the potential to be competitive with the lowest-cost uranium mining operations in the world. Permitting efforts for the planned Phoenix ISR operation commenced in 2019 and have advanced significantly, with licensing in progress and a draft environmental impact statement submitted for regulatory and public review in October, 2022. More information is available in the technical report, titled, "NI 43-101 Technical Report on the Wheeler River Project Athabasca Basin, Saskatchewan, Canada," dated Aug. 8, 2023, with an effective date of June 23, 2023, a copy of which is available on Denison's website and under its profile on SEDAR+ and on EDGAR.

About Denison Mines Corp.

Denison is a uranium exploration and development company with interests focused in the Athabasca basin region of Northern Saskatchewan, Canada. In addition to the company's effective 95-per-cent interest in its flagship Wheeler River uranium project, Denison's interests in Saskatchewan include a 22.5-per-cent ownership interest in the McClean Lake joint venture, which comprises several uranium deposits and the McClean Lake uranium mill that is contracted to process the ore from the Cigar Lake mine under a toll milling agreement, plus a 25.17-per-cent interest in the Midwest Main and Midwest A deposits, and a 67.41-per-cent interest in the Tthe Heldeth Tue (THT) and Huskie deposits on the Waterbury Lake property. The Midwest Main, Midwest A, THT and Huskie deposits are located within 20 kilometres of the McClean Lake mill.

Through its 50-per-cent ownership of JCU, Denison holds additional interests in various uranium project joint ventures in Canada, including the Millennium project (JCU, 30.099 per cent), the Kiggavik project (JCU, 33.8118 per cent) and Christie Lake (JCU, 34.4508 per cent).

Denison's exploration portfolio includes further interests in properties covering approximately 285,000 hectares in the Athabasca basin region.

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