• New assays from RK-25-227 return 12.0 m at 3.46% U₃O₈, including 2.5 m at 14.9% U₃O₈ and 0.5 m at 31.0% U₃O₈.

• All 2024 assays received

• Completed assays adding to the best intercepts previously disclosed in holes RK-25-232 (15.0 m at 15.9% U₃O₈ including 3.0 m at 47.8% U₃O₈, 1.5 m at 29.4% U₃O₈ and 0.5 m at 68.8% U₃O₈) and RK-24-222 (17.0 m at 3.85% U₃O₈).

NexGen Energy Ltd. (TSX: NXE) (NYSE: NXE) (ASX: NXG)  is pleased to announce additional exciting 2024 and winter 2025 assay results from exploration at Patterson Corridor East. Assays from 2024 are now fully received (Table 1).

New assays received from early winter 2025 with RK-25-227 returning 12.0 meters (m) at 3.46% U₃O₈ including 2.5 m at 14.9% U₃O₈ and an impressive 31.0% U₃O₈ over 0.5 m (Figure 1, Table 2). RK-25-227 is located 100 m down plunge of hole RK-25-232, and 100 m up dip from RK-24-222, demonstrating the continuity of this high-grade mineralization.

Leigh Curyer, Chief Executive Officer, commented: “These new assays demonstrate PCE’s high grade intensity and scale of mineralization, reflecting the emergence of a second major high-grade mineralized system 3.5km to the east of Arrow. To date, PCE is mirroring Arrow in many respects – basement hosted with a high grade sub-domain. Drilling will continue to systematically test both the overall footprint extent and inner high grade sub-domain at PCE which both remain open in all directions.

As demand for nuclear power continues to grow and Big Tech companies alongside global policy makers and a wide range of industries continue to adopt nuclear power. The demand is increasing considerably faster than ever anticipated and the opportunity for the southwest section of the Athabasca Basin in Saskatchewan to service this worldwide demand is massive for local communities, Saskatchewan and Canada. NexGen will continue to add resources through its efficient discovery and delineation of uranium resources to its already world recognized Rook I Project and prospective land holdings that remains over 95% unexplored.”

Jason Craven, Vice President, Exploration, commented: “With the complete assay results for 2024 and early 2025, we are excited by the rapid growth of this material discovery and the similarities it exhibit to Arrows. The majority of the 2025 drill campaign remains ahead of us and the team is intensely focused on further unlocking the scale of PCE in the same cost and time efficient manner delivered with Arrow.”

Figure 1: Core photo of assays from RK-25-227, grades are shown as % U₃O₈

 Figure 2: Interpreted model of mineralization at PCE (as of this release) with newly received assay results highlighted; view is a long section that looks perpendicular to the primary mineralized plane; total mineralized footprint in orange and the high-grade subdomains in red

Table 1: 2024 Assays received since May 27 news release

• All depths and intervals are meters downhole, true thicknesses are yet to be determined.
• Unconformity of ‘N/A’ denotes a lack of visible contact between Athabasca sandstone and basement rock.
• Maximum internal dilution 2.0 m downhole.
• Minimum thickness of 0.5 m downhole.
• Cutoff grade 0.01% U₃O₈.
• All depths and intervals are meters downhole, true thicknesses are yet to be determined. Resource modelling in conjunction with an updated mineral resource estimate is required before true thicknesses can be determined.
• * Results for RK-24-222 from 604.5 to 621.5 m previously reported on May 27, 2025 and shown here for complete reference

Table 2: 2025 Assay results received since May 27 news release

• All depths and intervals are meters downhole, true thicknesses are yet to be determined.
• Unconformity of ‘N/A’ denotes a lack of visible contact between Athabasca sandstone and basement rock.
• Maximum internal dilution 2.0 m downhole.
• Minimum thickness of 0.5 m downhole.
• Cutoff grade 0.01% U₃O₈.
• All depths and intervals are metres downhole, true thicknesses are yet to be determined. Resource modelling in conjunction with an updated mineral resource estimate is required before true thicknesses can be determined.
• * Denotes results that correlate to high-grade levels of radioactivity (>10,000 cps)
• ** Results for RK-25-232 from 388.0 to 440.0 m and 452.0 to 467.0 m previously reported on May 27, 2025 and shown here for complete reference.

About NexGen

NexGen Energy is a Canadian company focused on delivering clean energy fuel for the future. The Company’s flagship Rook I Project is being optimally developed into the largest low-cost producing uranium mine globally, incorporating the most elite environmental and social governance standards. The Rook I Project is supported by an N.I. 43-101 compliant Feasibility Study, which outlines the elite environmental performance and industry-leading economics. NexGen is led by a team of experienced uranium and mining industry professionals with expertise across the entire mining life cycle, including exploration, financing, project engineering and construction, operations and closure. NexGen is leveraging its proven experience to deliver a Project that leads the entire mining industry socially, technically and environmentally. The Project and prospective portfolio in northern Saskatchewan will provide generational, long-term economic, environmental, and social benefits for Saskatchewan, Canada, and the world.