Athabasca Oil Announces 2025 Year-end Results and Reserves

Press Release

March 4, 2026

CALGARY – Athabasca Oil Corporation (TSX: ATH) (“Athabasca” or the “Company”) is pleased to report its audited 2025 year-end results and reserves. The annual results are highlighted by strong operational performance across all assets, resilient financial performance, and execution of continued shareholder returns. Athabasca provides investors unique positioning to top tier liquids weighted assets (Thermal Oil and Duvernay) with a focus on maximizing cash flow per share growth by investing in competitive projects alongside a return of capital framework focused on share buybacks.

Year-end 2025 Consolidated Corporate Results

⦁ Production: Average annual production of 39,375 boe/d (98% Liquids), representing 7% (17% per share) growth year-over-year. Strong performance across all assets supported the Company reaching the high-end of its guidance of 37,500 – 39,500 boe/d. Thermal Oil annual production was 35,905 bbl/d and Duvernay Energy Corporation (“DEC”) annual production was 3,470 boe/d (76% Liquids). Fourth quarter consolidated production was 41,061 boe/d (98% Liquids).

⦁ Cash Flow: Adjusted Funds Flow of $504 million ($1.01 per share). Cash flow from operating activities of $520 million. Free Cash Flow of $217 million from Athabasca (Thermal Oil) demonstrates the resilience of a quality asset base and clean balance sheet. DEC growth was self-funded separately within its cash flow and balance sheet.

⦁ Capital Program: $323 million total capital expenditures, consistent with guidance, including $231 million at Leismer to support the progressive growth project and $75 million in Duvernay development.
⦁ Shareholder Returns: Purchased 39 million shares through the Company’s buyback program for an aggregate $230 million, demonstrating its commitment to return 100% of Free Cash Flow to shareholders in 2025. The Company has now purchased ~$720 million in shares and has reduced its fully diluted share count by 24% since commencing the buyback program in 2023. Following the expiry of its current Normal Course Issuer Bid (“NCIB”) on March 17, 2026 the Company will renew a fourth annual NCIB with the Toronto Stock Exchange.

2025 Year-end Consolidated Reserves1

⦁ Differentiated Long-life Reserves: Athabasca holds 1.3 billion boe of Proved Plus Probable (“2P”) reserves and ~1 billion barrels of Contingent Resource (Best Estimate). The 2P reserves underpin significant intrinsic value of $5.8 billion NPV102 ($12.13 per share).
⦁ Deep Value with Funded Growth Optionality within Thermal Oil: The Thermal Oil division has a 2P NPV102 of $5.2 billion and provides an oil focused platform underpinning funded growth to >60,000

Footnote: Refer to the “Reader Advisory” section within this news release for additional information on Non-GAAP Financial Measures (e.g. Adjusted Funds Flow, Free Cash Flow, Sustaining Capital, Net Cash) and production disclosure.
⦁ Consolidated reserves reflect gross reserves and financial metrics before taking into account Athabasca’s 70% equity interest in Duvernay Energy.
2 Net present value of future net revenue before tax at a 10% discount rate (NPV 10 before tax) for 2025 is based on an average of McDaniel, Sproule and GLJ pricing as at January 1, 2026.

3Pricing Assumptions: 2026+ US$65 WTI, US$12.50 WCS heavy differential, C$3 AECO, and 0.725 C$/US$ FX.
4The Company’s illustrative multi-year outlook assumes 100% of Free Cash Flow is directed to share buybacks up to a 10% Normal Course Issuer Bid limit at an implied share price of 6x Enterprise Value/Debt Adjusted Cash Flow in 2027 and beyond.

bbl/d by 2030 with Phase 1 of Corner. The Company’s growth outlook will accelerate an unparalleled ~30 year 1P and ~85 year 2P current reserve life.

⦁ Duvernay Value Capture: DEC 2P reserves increased by 9% to 79 mmboe, representing a NPV102 value of $592 million. Continued growth is attributed to development on its operated lands. DEC has an estimated 432 gross drilling locations (198 net) across its ~200,000 gross acre land base.

2026 Guidance Maintained

⦁ Consolidated Budget: Athabasca is planning capital expenditures of ~$310 million with average production of 37,000 – 39,000 boe/d (98% Liquids), inclusive of a ~2,500 boe/d impact of planned turnarounds across its assets. Growth will materialize in the second half of 2026 with an exit rate of ~43,000 boe/d, driven by the Leismer expansion project. Strong operational momentum is expected to continue into 2027 as Leismer ramps up to regulatory capacity and additional Duvernay production is added.

⦁ Cash Flow Outlook: The Company forecasts consolidated Adjusted Funds Flow between $425 – $450 million3 in 2026. With operational momentum into 2027, Adjusted Funds Flow and Free Cash Flow are expected to grow significantly year over year. Every +US$1/bbl move in West Texas Intermediate (“WTI”) and Western Canadian Select (“WCS”) heavy oil impacts 2026 annual Adjusted Funds Flow by ~$10 million and ~$17 million, respectively.

⦁ Balance Sheet Management: Athabasca will prudently manage its capital structure as operations increase in scale. A Net Cash position currently provides the Company capital allocation flexibility for its business initiatives including multi-year capital projects and augmenting strategic share buybacks. Athabasca is committed to maintaining a best-in-class balance sheet with a targeted Net Debt to Adjusted Funds Flow metric less than 0.5x over the long-term.

Operations Update

⦁ Leismer Expansion On Track: The winter drilling program will conclude in March and includes twelve well pairs that will be commissioned and steamed in the second half of the year. In conjunction with the planned facility additions that will be completed during the turnaround in May, these well pairs will drive strong production momentum exiting the year and progressive growth up to 40,000 bbl/d in late 2027.

⦁ Hangingstone Resilience: Current production of ~9,000 bbl/d following the addition of two well pairs in 2025. No additional drilling is required in 2026 to maintain production above a mid-term target at the asset of 8,000 bbl/d. Hangingstone will also undergo a planned turnaround in April.

⦁ Corner Readiness: The Corner asset will be developed through a capital-efficient modular design with 15,000 bbl/d project phases. Current activity includes central processing facility, road and pad-site preparation during the winter construction season. The Company has finalized cost estimates and is advancing lump-sum execution structures to enhance certainty over project cost and schedule. Additionally, the Company has secured critical path contracts including gas feedstock and diversified long-term egress. The Company anticipates Phase 1 to be sanctioned in the second half of 2026, contingent on a favorable macro environment, with the majority of the capital to follow the current

Leismer expansion project. The project is expected to be self-funded while maintaining a strong balance sheet and a focus on shareholder returns. Phase 1 will provide substantial production growth starting in 2029.

⦁ Exceptional Duvernay Well Results: Wells brought on stream in the second half of 2025 demonstrated continued strong performance validating type-curves and longer-term development plans. The operated three-well pad at 4-18-64-16W5 (100% WI) has now realized average IP90s of ~945 boe/d (89% Liquids). An additional 4-well pad at 7-15-64-17 W5 (30% WI) was rig released in February with completions underway and a planned onstream date in April. The Company is pleased by the strong production results with initial rates and free condensate yields resulting in exceptional netbacks. DEC will preserve its valuable inventory during periods of market volatility with flexibility to accelerate development in supportive macro conditions.

Corporate Consolidated Strategy

⦁ Thermal Oil Scale: The Company’s Thermal Oil division provides an oil focused platform underpinning funded growth to >60,000 bbl/d by 2030 with Phase 1 of Corner. The Thermal Oil assets have a resource base of 1.2 billion barrels of proved plus probable reserves and 1 billion barrels of contingent resource, providing optionality to reach over 90,000 bbl/d within current regulatory approvals. The Thermal Oil assets have an operating break-even of ~US$40/bbl WTI, a sustaining break-even of ~$US45/bbl WTI and growth initiatives at Leismer and Corner are fully funded within cash flow to ~US$55/bbl WTI.

⦁ Duvernay Value Proposition: Athabasca’s subsidiary company, Duvernay Energy Corporation (“DEC”), is designed to enhance value for shareholders by providing a clear path for self-funded production and cash flow growth in the Kaybob Duvernay resource play. DEC has an independent strategy and capital allocation framework with production growth to >15,000 boe/d by 2030 with ~20 years of future drilling inventory. Value crystallization for shareholders is expected once the asset has reached a material scale through its exceptional land base and drilling inventory.

⦁ Financial Resilience: Athabasca maintains a strong and differentiated balance sheet with a $59 million consolidated Net Cash position, including $316 million of cash. The Company will prudently manage its capital structure as operations increase in scale. A Net Cash position currently provides the Company capital allocation flexibility for its business initiatives including multi-year capital projects and augmenting strategic share buybacks. Athabasca is committed to maintaining a best-in-class balance sheet with a targeted Net Debt to Adjusted Funds Flow metric less than 0.5x over the long-term. Athabasca (Thermal Oil) also has $2.1 billion in tax pools, including $1.6 billion of immediately deductible non-capital losses, sheltering cash taxes beyond 2030.

⦁ Exceptional Shareholder Returns: The Company has returned ~$1.1 billion to shareholders since 2021, including $386 million of debt reduction and ~$720 million of share buybacks. The buyback program has driven a 24% reduction in fully diluted shares since 2023 at an average price of $4.82/sh, representing a ~60% discount to its 2025 2P reserves value per share of $12.132. Share buybacks remain an important capital allocation tool where valuation supports compelling risk-adjusted returns
relative to intrinsic net asset value. Athabasca is committed to returning 100% of Free Cash Flow to

shareholders through share buybacks in 2026. Any repurchases beyond Free Cash Flow will be undertaken selectively and within a disciplined framework that prioritizes funding the Company’s core growth projects and maintaining a strong balance sheet. Athabasca forecasts $1.1 billion3 of additional Free Cash Flow over the next five years while funding its growth initiatives at Leismer and Corner.

⦁ Focus on Per Share Metrics: Advancing attractive capital projects concurrent with share buybacks results in a >20% compounded annual growth rate in cash flow per share4 to 2030 and beyond.

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