Mr. Keith Bodnarchuk reports

COSA ANNOUNCES C$5 MILLION PRIVATE PLACEMENT, INCLUDING PARTICIPATION BY DENISON MINES

Cosa Resources Corp. has entered into an agreement with Haywood Securities Inc., on behalf of itself and a syndicate of agents to include Velocity Capital Partners, which have agreed to sell, on a commercially reasonable efforts private placement basis, any combination of: (i) hard-dollar units of the company at a price of 26 cents per unit for minimum gross proceeds of $2-million; (ii) charity flow-through units of the company at a price of 39.8 cents per charity FT unit; and (iii) flow-through common shares of the company at a price of 30 cents per FT share, for aggregate gross proceeds to the company of up to $5-million.

Cosa's largest shareholder, Denison Mines Corp., has indicated that it will participate in the offering at a price of 26 cents per unit up to an amount that will maintain its holdings in Cosa at approximately 19.95 per cent (on a partially diluted basis) following the completion of the offering, pursuant to its pre-emptive and top-up rights under the investor rights agreement between Denison and Cosa dated Jan. 14, 2025. Denison is a leading Athabasca basin-focused uranium mining, development and exploration company with a market capitalization of over $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.

Immediately prior to the date hereof, Denison beneficially owned, directly or indirectly, or exercised control or direction over, 16,723,172 common shares and warrants to purchase an additional 1,263,833 common shares, representing approximately 18.8 per cent of the issued and outstanding common shares on a non-diluted basis, and approximately 19.9 per cent on a partially diluted basis. Denison does not yet know the exact number of common shares and warrants it will beneficially own, directly or indirectly, or exercise control or direction upon closing of the offering, nor the percentage of the issued and outstanding common shares on a non-diluted basis and, assuming the exercise of all warrants now held by Denison on a partially diluted basis.

Denison's purchase of the units under the offering is being made for investment purposes. Denison may determine to increase or decrease its investment in the company depending on market conditions and any other relevant factors. This release is required to be issued under the early warning requirements of applicable securities laws. Denison's head office is located at Suite 1100, 40 University Ave., Toronto, Ont., M5J 1T1. In satisfaction of the requirements of National Instrument 62-104, Take-Over Bids And Issuer Bids, and National Instrument 62-103, The Early Warning System and Related Take-Over Bid and Insider Reporting Issues, an early warning report respecting the acquisition of common shares and warrants to purchase additional common shares by Denison will be filed under the company's SEDAR+.

Keith Bodnarchuk, president and chief executive officer of Cosa, commented: "Cosa's upcoming exploration plans will make for an active and exciting year for the company as we work towards drilling highly compelling targets at both the Murphy Lake North and Darby joint venture projects, which Cosa operates in partnership with our largest shareholder Denison. We thank Denison for their direct participation in this financing and recognize it as a strong endorsement of our team and the upside potential of our winter drill targets. Denison's ongoing commitment as both a large shareholder and joint venture partner continues to provide Cosa with the technical and financial support to pursue our objective of making the next great uranium discovery in Saskatchewan's Athabasca basin."

Each FT share will qualify 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 will consist of one common share of the company plus one-half of one common share purchase warrant. Each charity FT unit will consist of one FT share plus one-half of one warrant. Each warrant will entitle the holder thereof to purchase one common share of the company at an exercise price of 37 cents for 24 months following the closing date (as defined below).

In addition, the company has granted the agents an option, exercisable in whole or in part by the agents, at any time up to 48 hours prior to the closing date (as defined below), to purchase up to an additional 15 per cent of offered Securities, in any combination of units, charity FT units and/or FT shares, at the respective issue prices above.

The company understands that purchasers of the charity FT units may immediately resell or donate some or all of the charity FT units to registered charities, who may sell such units concurrent with closing of the offering to purchasers arranged by the agents at a price per resale unit equal to the unit issue price.

The company intends to use the net proceeds from the sale of units to finance 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 Dec. 31, 2026. All qualifying expenditures will be renounced in favour of the subscribers of the charity FT units and FT shares effective Dec. 31, 2025.

Subject to compliance with applicable regulatory requirements and in accordance with National Instrument 45-106, Prospectus Exemptions, the offered securities will be offered by way of the accredited investor, family, friends and business associates, and minimum amount investment exemptions under NI 45-106 in all of the provinces of Canada, or in the case of the units, also in offshore jurisdictions and the united States on a private placement basis pursuant to one or more exemptions from the registration requirements of the U.S. Securities Act. The unit shares, FT shares and warrant shares issuable pursuant to the offering will be subject to a hold period ending on the date that is four months plus one day following the closing date under applicable Canadian securities laws.

The offering is expected to close on or about Dec. 4, 2025 (the closing date), or such other date as the company and the agents may agree, and is subject to certain conditions, including, but not limited to, receipt of all necessary approvals, including the approval of the TSX Venture Exchange.

The company will pay to the agents a cash commission of 5.0 per cent of the gross proceeds raised in respect of the offering, other than in respect of up to $1.5-million in offered securities issued to certain purchasers on a president's list to be agreed upon by the company and the agents (the president's list), in which case the commission in respect of such issuance shall be equal to 3.0 per cent. In addition, the company will issue to the agents compensation options, exercisable for a period of 24 months following the closing date, to acquire in aggregate that number of common shares that is equal to 6.0 per cent of the number of offered securities sold under the offering at an exercise price equal to the unit issue price, other than in respect of offered securities issued to purchasers on the president's list, in which case the company will not issue any compensation options.

About Cosa Resources Corp.

Cosa Resources is a Canadian uranium exploration company operating in northern Saskatchewan. The portfolio comprises roughly 237,000 hectares across multiple underexplored 100-per-cent-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 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 two kilometres of strike length.

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