Mr. Keith Bodnarchuk reports

COSA ANNOUNCES COMMENCEMENT OF WINTER 2026 DRILLING CAMPAIGN ON JOINT VENTURES WITH DENISON MINES

Drilling has commenced at Cosa Resources Corp.'s Darby project, with drilling at Murphy Lake North (MLN) to follow. Darby and MLN are joint ventures between Cosa and Denison Mines Corp., and are located 10 kilometres west of Cameco's Cigar Lake mine and three kilometres east of IsoEnergy's Hurricane deposit, respectively, in the eastern Athabasca basin, Saskatchewan. Cosa is the operator of both projects and holds a 70-per-cent interest with Denison holding a 30-per-cent interest in each.

Winter drilling

Approximately 2,500 metres are planned at Darby in winter 2026 to test initial priority targets identified by Cosa's 2025 core relogging and reinterpretation program. Priority targets are the immediate vicinities of drill holes which intersected zones of coincident sandstone alteration and anomalous uranium content proximal to significant graphitic basement faults. Up to four initial target areas will be evaluated during winter 2026.

Drilling plans at MLN comprise approximately 1,200 metres and will follow up summer 2025 results at the Cyclone trend where broad zones of structure and alteration were intersected over a two-kilometre strike length. Drilling will target a 1,200-metre gap in existing drilling where a lake prevents summer access. Drilling will also test a potential trend parallel to and approximately 100 metres south of Cyclone interpreted from intensely graphitic rocks and faulting intersected in the basement of MLN25-007.

For further details on winter 2026 drill targets, refer to Cosa's news release dated Jan. 21, 2026.

About Darby

Located 10 kilometres west of the Cigar Lake mine, Darby contains multiple prospective conductive trends and several historical intersections of weak uranium mineralization. Historical drilling demonstrates that many of these trends are highly prospective for uranium deposits characteristic of the eastern Athabasca basin, yet most of the strike length has not been effectively evaluated. Work by Cosa in 2025 prioritized these trends and identified several historical drill holes with results that suggest proximity to uranium mineralization (see Cosa's news releases dated Oct. 24, 2025, and Jan. 21, 2026). Darby was last drilled in 2009.

About Murphy Lake North

MLN covers a portion of the Larocque Lake trend and is located 2.7 kilometres east of the Hurricane deposit. Hurricane is the world's highest-grade indicated uranium resource and was discovered and delineated for IsoEnergy Ltd. by current members of Cosa's team. The Larocque Lake trend also hosts the high-grade Larocque Lake zone, Yelka prospect and Alligator Lake zone. MLN contains the along-strike extension of basement geology underlying the Hurricane deposit (the Hurricane trend), as well as a parallel conductive trend to the south (the Cyclone trend). Drilling by Cosa in 2025 intersected zones of sandstone alteration and structure associated with graphitic basement structures along both trends. Following up these positive results is the primary 2026 objective at MLN.

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 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 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 held key roles in the founding of both NexGen and IsoEnergy.

The company's focus throughout 2026 is drilling at the Darby and MLN 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 will evaluate target areas with anomalous uranium, clay alteration and historical mineralization intersected nearby. Drilling at MLN will follow up 2025 drilling which intersected broad zones of structurally controlled alteration over roughly two kilometres of strike length.

Technical disclosure

Historical drilling and geophysical results for Darby and MLN were sourced from the Saskatchewan Mineral Assessment Database (SMAD). SMAD sources for Darby include file numbers 74H14-0021, 74H14-0023, 74H15-0041, 74H15-0053, 74H15-0055, 74H15-0056, 74H15-0066, 74H15-0067, 74I02-0031, 74I02-0042, 74I02-0053, 74I02-0080, 74I02-0095 and MAW00516. Some confidential data and reports not presently available via SMAD were supplied to Cosa by Denison. SMAD sources for MLN and adjacent projects include file numbers 64L05-0161, 64L05-0180, 74I-0060, 74I-0066, 74I-0067, 74I01-0114, 74I08-0056, 74I09-0053, 74I09-0057, 74I09-0061, 74I09-0064, 74I09-0066, 74I09-0071, 74I09-0077, 74I09-0079, 74I09-0087, 74I09-0088, 74I09-0090, 74I09-0091, 74I09-0092, 74I09-0098, MAW00510, MAW01939, MAW02327, MAW02599 and MAW02395. Data and reports related to the 2020 ground EM survey completed by Denison are not presently available via SMAD and were supplied to Cosa by Denison.

Verification of historical drilling results included confirming historical drill hole collar locations from air photos and ground checking selected collars with a handheld GPS unit. Basement and lower sandstone sections from most historical drill holes were relogged in 2024 and 2025 by Cosa. For Darby, verification of geochemical results for drill holes completed between 2008 and 2010 was facilitated by the reissuance of analytical certificates to Cosa by the Saskatchewan Research Council (SRC). Cosa thanks the SRC for its valued assistance in increasing confidence in the historical data set.

Verification of historical geophysical results included confirming the locations of geophysical survey grids from air photos, compiling survey data and interpretations, and evaluating whether interpreted geophysical results could be reasonably explained by historical and current drilling results. For MLN, Cosa engaged a consultant to re-interpret historical geophysical surveys to validate selected previous interpretations.

Qualified person

The company's disclosure of technical or scientific information in this press release has been reviewed and approved by Andy Carmichael, PGeo, vice-president, exploration, for Cosa. Mr. Carmichael is a qualified person as defined under the terms of National Instrument 43-101. This news release refers to neighbouring properties in which the company has no interest. Mineralization on those neighbouring properties does not necessarily indicate mineralization on the company's properties.

We seek Safe Harbor.