Mr. Keith Bodnarchuk reports

COSA CLOSES C$6 MILLION PRIVATE PLACEMENT, INCLUDING FULL EXERCISE OF OVER-ALLOTMENT OPTION

Cosa Resources Corp. has closed the brokered private placement previously announced by the company on Feb. 4, 2025, including the full exercise of the overallotment option, for aggregate gross proceeds of approximately $6-million. The offering was completed through a syndicate of agents, led by Haywood Securities Inc. and including Red Cloud Securities Inc.

Cosa's largest shareholder, Denison Mines Corp., participated in the offering pursuant to its pre-emptive and top-up rights under the investor rights agreement between Denison and the company dated Jan. 14, 2025. Upon completion of the offering, Denison owns a 19.95-per-cent ownership 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 $2-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 8.8 million units of the company at a price of 25 cents per unit and 8,941,176 charity flow-through (FT) units of the company at a price of 42.5 cents per charity FT unit.

Each unit consists of one common share of the company and one-half of one common share purchase warrant. Each charity FT unit consists of one share of the company that 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), and one-half of one warrant. Each warrant entitles the holder to purchase one share at an exercise price of 37 cents until Feb. 26, 2027.

The gross proceeds from the sale of the charity FT units 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 in Saskatchewan, on or before Dec. 31, 2026. All qualifying expenditures will be renounced in favour of the subscribers of the charity FT units effective Dec. 31, 2025. The net proceeds from the sale of the units will be used to finance exploration and for additional working capital purposes.

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 per cent 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 per cent; and (ii) issued compensation options of the company to the agents to acquire that number of common shares in the capital of the company that is equal to 6.0 per cent 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 March 5, 2026, at an exercise price of 25 cents.

The offered securities sold to purchasers not on the president's list were sold pursuant to the listed issuer financing exemption under Part 5A of National Instrument, Prospectus Exemptions, and therefore are not subject to resale restrictions pursuant to applicable Canadian securities legislation. The offered securities sold to purchasers on the president's list are subject to a hold period expiring on June 27, 2025.

Certain directors and officers of the company and Denison, and certain officers of Denison, subscribed for an aggregate of 2.97 million units for gross proceeds of $742,500 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 $2.5-million.

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 the 2,527,666 units on closing of the offering. Prior to the issuance of the units by Cosa, Denison held 14,195,506 shares, representing 19.95 per cent of Cosa's issued and outstanding shares. Immediately after giving effect to the offering, Denison had beneficial ownership of, or control and direction over, 16,723,172 shares, representing 18.81 per cent of the issued and outstanding shares of Cosa as of the date hereof, and 1,263,833 warrants, representing 14.25 per cent of the warrants issued and outstanding after the offering. The shares and warrants 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 the warrants, the terms of the acquisition agreement between Denison and Cosa dated Nov. 26, 2024, and/or its pre-emptive rights under the investor rights agreement. Further information is available in Cosa's news release dated Jan. 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 and commercial, info@denisonmines.com, at 1100, 40 University Ave., Toronto, Ont., M5J 1T1.

Further details about the offering can be found in the offering document related to the offering posted on the company website and on SEDAR+.

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 100-per-cent-owned and Cosa-operated joint venture projects in the Athabasca basin region, all of which are underexplored, and the majority reside within or adjacent to established uranium corridors.

Cosa's award-winning management team has a long record of success in Saskatchewan. In 2022, members of the Cosa team were awarded the AME Colin Spence Award for their previous involvement in discovering IsoEnergy's Hurricane deposit. Prior to Hurricane, 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.

In January of 2025, the company entered a transformative strategic collaboration with Denison that has secured Cosa access to 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 primary focus through 2024 was initial drilling at the 100-per-cent-owned Ursa project, which captures over 60 kilometres of strike length of the Cable Bay shear zone, a regional structural corridor with known mineralization and limited historical drilling. It potentially represents the last remaining eastern Athabasca corridor to not yet yield a major discovery, which the company believes is primarily due to a lack of modern exploration. Modern geophysics completed by Cosa in 2023 identified multiple high-priority target areas characterized by conductive basement stratigraphy beneath or adjacent to broad zones of inferred sandstone alteration, a setting that is typical of most eastern Athabasca uranium deposits. Guided by a recently completed ambient noise tomography (ANT) survey, Cosa's second and most recent drilling campaign at Ursa intersected a significant zone of unconformity-style sandstone-hosted structure and alteration underlain by several intervals of anomalous radioactivity in the basement rocks.

We seek Safe Harbor.