Cosa Resources Corp. (TSX-V: COSA) (OTCQB: COSAF) (FSE: SSKU) is pleased to announce that it has closed the brokered private placement previously announced by the Company on November 13, 2025, as upsized on November 14, 2025, for aggregate gross proceeds to the Company of C$7,500,000.74. The Offering was completed through a syndicate of agents, led by Haywood Securities Inc. and including Velocity Capital Partners and CIBC Capital Markets.

Cosa’s largest shareholder, Denison Mines Corp. (TSX: DML) (NYSE American: DNN), participated in the Offering pursuant to its rights under the investor rights agreement between Denison and the Company dated January 14, 2025. With closing of the Offering, Denison now owns 18.59% of Cosa on a partially-diluted basis. Denison is a leading Athabasca Basin-focused uranium mining, development, and exploration company with a market capitalization of approximately C$3 billion. Denison’s current focus is advancing the development-stage Wheeler River project, which represents one of the largest undeveloped uranium mining projects in the infrastructure rich eastern portion of the Athabasca Basin.

Pursuant to the Offering, the Company issued: (i) 11,538,462 hard dollar units of the Company at a price of C$0.26 per Unit; (ii) 7,537,690 charity flow-through units of the Company at a price of C$0.398 per Charity FT Unit; and (iii) 5,000,000 flow-through common shares of the Company at a price of C$0.30 per FT Share.

Each FT Share qualifies as a “flow-through share” within the meaning of the Income Tax Act (Canada) and will qualify as an “eligible flow-through share” as defined in The Mineral Exploration Tax Credit Regulations, 2014 (Saskatchewan). Each Unit consists of one common share of the Company plus one-half of one common share purchase warrant. Each Charity FT Unit consists of one FT Share plus one-half of one Warrant. Each Warrant entitles the holder thereof to purchase one common share of the Company at an exercise price of C$0.37 until December 4, 2027.

The Company will use the net proceeds from the sale of Units to fund exploration and for additional working capital purposes. The gross proceeds from the sale of Charity FT Units and FT Shares will be used by the Company to incur eligible “Canadian exploration expenses” that qualify as “flow-through critical mineral mining expenditures” as such terms are defined in the Income Tax Act (Canada), and to incur “eligible flow-through mining expenditures” pursuant to The Mineral Exploration Tax Credit Regulations, 2014 (Saskatchewan) related to the Company’s uranium projects in the Athabasca Basin, Saskatchewan, on or before December 31, 2026. All Qualifying Expenditures will be renounced in favour of the subscribers of the Charity FT Units and FT Shares effective December 31, 2025.

In consideration for the services provided by the Agents in connection with the Offering, on closing the Company: (i) paid to the Agents a cash commission equal to 5.0% of the gross proceeds of the Offering, other than in respect of Offered Securities issued to certain purchasers on a president’s list agreed upon by the Company and the Agents, in which case the commission in respect of such issuance was equal to 3.0%; and (ii) issued compensation options of the Company to the Agents to acquire that number of common shares in the capital of the Company which is equal to 6.0% of the number of Offered Securities sold under the Offering, other than in respect of Offered Securities issued to purchasers on the President’s List, in which case the Company did not issue any Compensation Options. Each Compensation Option entitles the holder to acquire one Compensation Option Share until December 4, 2027, at an exercise price of C$0.26.

The Offered Securities are subject to a hold period expiring on April 5, 2026.

Certain directors and officers of the Company, Denison, and certain officers of Denison subscribed for an aggregate of 2,607,692 Units and 616,669 FT Shares for gross proceeds of C$863,000.62 under the Offering. Participation by these insiders of the Company in the Offering constitutes a related-party transaction as defined under Multilateral Instrument 61-101 – Protection of Minority Security Holders in Special Transactions. The issuance of these securities is exempt from the formal valuation requirements of Section 5.4 of MI 61-101 pursuant to Subsection 5.5(b) of MI 61-101 as the Shares are listed on the TSX Venture Exchange. The issuance of these securities is also exempt from the minority approval requirements of Section 5.6 of MI 61-101 pursuant to Subsection 5.7(1)(b) of MI 61-101 as the fair market value was less than C$2,500,000.

Denison will be filing an early warning report, under National Instrument 62-103 – The Early Warning System and Related Take-Over Bid and Insider Reporting Issues in respect of the acquisition by Denison of 2,307,692 Units on closing of the Offering. Prior to the issuance of the Units by Cosa, Denison held 16,723,172 Shares and 1,263,833 common share purchase warrants, representing 19.95% of Cosa on a partially-diluted basis. Immediately after giving effect to the Offering, Denison had beneficial ownership of, or control and direction over, 19,030,864 Shares, representing 16.85% of the issued and outstanding Shares of Cosa as of the date hereof and 2,417,679 common share purchase warrants, representing 9.81% of the warrants issued and outstanding after the Offering. The Units were acquired by Denison for investment purposes. Denison intends to review, on a continuous basis, various factors related to its investment in Cosa, and may decide to acquire or dispose of additional securities of Cosa as future circumstances may dictate, including pursuant to the exercise of warrants, the terms of the Acquisition Agreement between Denison and Cosa dated November 26, 2024 and/or its pre-emptive rights under the Investor Rights Agreement. Further information is available in Cosa’s press release dated January 14, 2025, in the early warning report to be filed by Denison under Cosa’s profile on SEDAR+ or by contacting Denison:

Geoff Smith, Vice President Corporate Development & Commercial
Denison Mines Corp.
info@denisonmines.com
Suite 1100 – 40 University, Toronto, Ontario M5J 1T1

The Offered securities described in this news release have not been, nor will they be, registered under the United States Securities Act of 1933, or any United States state securities laws, and may not be offered or sold, directly or indirectly, within the United States or to, or for the account or benefit of, U.S. persons absent registration or an exemption from registration requirements. This news release does not constitute an offer for sale of securities, nor a solicitation for offers to buy any securities in the United States, not in any other jurisdiction in which such offer, solicitation or sale would be unlawful.

The terms “Unites States” and “U.S. person” used herein are as defined in Regulation S under the U.S. Securities Act.

About Cosa Resources Corp.

Cosa Resources is a Canadian uranium exploration company operating in northern Saskatchewan. The portfolio comprises roughly 237,000 ha across multiple underexplored 100% owned and Cosa-operated joint venture projects in the Athabasca Basin region, the majority of which reside within or adjacent to established uranium corridors.

In January of 2025, the Company entered a transformative strategic collaboration with Denison Mines that has secured Cosa access into several additional highly prospective eastern Athabasca uranium exploration projects. As Cosa’s largest shareholder, Denison gains exposure to Cosa’s potential for exploration success and its pipeline of uranium projects.

Cosa’s award-winning management team has a track record of success in Saskatchewan. In 2022, members of the Cosa team were awarded the AME Colin Spence Award for the discovery of the Hurricane uranium deposit. Cosa personnel led teams or had integral roles in the discovery of Denison’s Gryphon deposit and 92 Energy’s GMZ zone and held key roles in the founding of both NexGen and IsoEnergy.

The Company’s focus throughout 2026 is drilling at the Darby and Murphy Lake North projects in the eastern Athabasca Basin. Both projects are operated by Cosa and are 70/30 joint ventures between Cosa and Denison respectively. Drilling at Darby is planned to test priority targets identified by thorough review of historical data and drill core and will target areas with anomalous uranium, clay alteration, and historical mineralization intersected nearby. Drilling at Murphy Lake North will follow up 2025 drilling which intersected broad zones of structurally controlled alteration over roughly 2 kilometres of strike length.