TVE M&A announcement Report

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Tamarack Valley Energy and Headwater ExploraƟon Announce $10 Billion Strategic CombinaƟon to Create a Premier North American Oil Producer and a New Growth- Oriented ExploraƟon Company Calgary, Alberta – September 8, 2026 – Tamarack Valley Energy Ltd. (TSX: TVE) (“Tamarack”) and Headwater ExploraƟon Inc. (TSX: HWX) (“Headwater”) are pleased to announce they have entered into a deﬁniƟve arrangement agreement whereby the two companies will merge in an all-stock transacƟon valued at $10 billion (the “TransacƟon”), creaƟng a premier North American oil company that combines top-Ɵer proﬁtability with an unmatched posiƟon as the only publicly-traded pure-play Clearwater producer. Under the terms of the TransacƟon, Headwater shareholders will receive 1.0 common share of Tamarack for each Headwater common share held, resulƟng in Tamarack issuing a total of 237.8 million common shares to acquire all of the issued and outstanding common shares of Headwater. Following the closing of the TransacƟon, Tamarack shareholders will own 66.5% and Headwater shareholders will own 33.5% of the total common shares outstanding in the combined enƟty. The combined company, led by current Tamarack management, is expected to have run-rate pro forma Clearwater producƟon of >80,000 boe per day(2), net cash(1) of >$50 million and available funding(1) of >$1.2 billion. In connecƟon with the TransacƟon, Tamarack plans to increase its quarterly dividend by 20% from $0.05 per share to $0.06 per share ($0.24 per share annualized), commencing December 2026. The TransacƟon brings together two leading Clearwater producers, each characterized by low-cost, high-margin producƟon, low corporate decline rates, modest reinvestment requirements and low corporate breakeven oil prices. The combined business will beneﬁt from decades of Clearwater drilling and waterﬂood inventory, meaningful operaƟng and capital synergies and greater scale across the play. Shareholders will have exposure to a unique and diﬀerenƟated value proposiƟon from the enhanced eﬃciency, proﬁtability and durability of a combined Clearwater asset base. The TransacƟon is expected to be immediately accreƟve to Tamarack’s free funds ﬂow per share(1), enhance its ﬁve-year plan and posiƟon the combined company to deliver higher total returns to shareholders. In addiƟon, certain non-core exploraƟon assets will be transferred into Tributary ExploraƟon Inc. (“Tributary ExploraƟon”), a new exploraƟon company, providing Tamarack and Headwater shareholders with conƟnued exposure to these prospecƟve assets under the leadership of the current Headwater management team. Highlights of the TransacƟon  DiﬀerenƟated Clearwater Focus - The TransacƟon will establish Tamarack as a premier North American oil producer valued at $10 billion with excepƟonal economics. Tamarack will be a diﬀerenƟated market leader as the only publicly-traded pure- play Clearwater company and the largest Clearwater producer. The combined company will create a highly conƟguous core land posiƟon at Marten Hills, Nipisi and Marten Hills West bringing together two complementary asset bases with signiﬁcant depth of quality inventory.  Enhanced Scale & Depth of Quality Inventory - The TransacƟon is expected to result in a pro forma land posiƟon of >1,500 secƟons across the greater Clearwater fairway, >300 million boe of proved and probable reserves(2) across all formaƟons, low-decline run-rate producƟon(2) of >80,000 boe per day and >3,000 idenƟﬁed drilling locaƟons(2), supporƟng a long runway of high-quality development inventory. The TransacƟon more than doubles Tamarack’s exisƟng footprint at Pelican and Seal, providing the combined company with greater exposure to upside potenƟal on prospecƟve Clearwater and Wabiskaw targets in the Greater Clearwater fairway.  Immediately AccreƟve to Financial and OperaƟng Metrics - The TransacƟon is expected to be immediately accreƟve to Tamarack’s free funds ﬂow per share of >10% and its exisƟng ﬁve-year plan, while also improving Tamarack’s operaƟng proﬁle through a lower 2027 decline of 15% and a reduced free funds ﬂow breakeven cost(1) of US$37 per bbl (unhedged).  Leading Financial Strength & Capital AllocaƟon Flexibility - At closing, the combined company is expected to have net cash(1) of >$50 million and available funding(1) of >$1.2 billion providing substanƟal ﬂexibility to fund development, return capital to shareholders and pursue strategic opportuniƟes while maintaining balance sheet strength. Available funding is expected to include a fully undrawn credit facility of $875 million maturing in May 2030.  Meaningful Synergy Capture - The combined company is expected to realize immediate synergies through the integraƟon of operaƟons, markeƟng and corporate oﬃces. Near-term synergies are also expected through the consolidaƟon and streamlining of the combined company’s exploraƟon and development programs starƟng in 2027. Run-rate synergies are expected to be over $50 million per year, or greater than $350 million over the development plan.

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 Enhanced Shareholder Returns - In connecƟon with the TransacƟon, Tamarack plans to increase its quarterly dividend by another 20% from $0.05 per share to $0.06 per share ($0.24 per share annualized), commencing December 2026. This represents Tamarack’s second dividend increase in 2026 demonstraƟng the strength of the combined business and commitment to shareholder returns. The increase to Tamarack’s dividend is conƟngent upon the closing of the TransacƟon.  ConƟnued Shared Upside ParƟcipaƟon - Shareholders of both Tamarack and Headwater will retain exposure to emerging exploraƟon and development opportuniƟes through Tributary ExploraƟon, a newly formed company led by the current Headwater management team. Tributary ExploraƟon is expected to be publicly-listed and well capitalized to fund emerging exploraƟon opportuniƟes. Pro Forma Outlook On a pro forma basis, Tamarack expects full year 2026 corporate producƟon(2) to average 65,500 - 67,500 boe per day, a 7% increase over previous guidance, reﬂecƟng the impact of the TransacƟon, which is expected to close mid-way through the fourth quarter of 2026. Run-rate producƟon(2) of the combined company is >80,000 boe per day. Assuming compleƟon of the TransacƟon, Tamarack’s full year 2026 capital program is expected to be $450 - 470 million reﬂecƟng incremental spending associated with Headwater’s planned capital program following the TransacƟon closing. The 2026 combined capital investment programs of both companies for the full year are expected to be approximately $700 million. Tamarack expects to remain ﬂexible with signiﬁcant opƟonality and balance sheet strength to maximize total shareholder returns across commodity price cycles. In the near-term, the combined company is expected to conƟnue execuƟng a disciplined capital management strategy targeƟng a balanced allocaƟon of Clearwater growth of 10-12% through its ﬁve-year plan (up from 8-10% for Tamarack prior to the TransacƟon) and enhanced shareholder returns in the form of an increased dividend and share buybacks. Egress Update Following the TransacƟon, Tamarack will be posiƟoned to accommodate expected growth in its Clearwater producƟon with exisƟng and planned pipe-connected transportaƟon egress into Edmonton, Alberta. Tamarack has also secured 35,000 barrels per day of potenƟal long-term egress out of Alberta. 25,000 bbl per day of Trans Mountain service to the west coast is expected to commence in the ﬁrst quarter of 2027, subject to the compleƟon of the Drag Reducing Agent expansion. 10,000 bbl per day of capacity on the proposed South Bow Prairie Connector pipeline will provide exposure to Cushing, Oklahoma and the US Gulf Coast, potenƟally starƟng by the end of 2028 if the project is approved and constructed. These expanded egress opƟons provide Tamarack with an opportunity to miƟgate the risk of local capacity constraints and obtain greater exposure to diversiﬁed oil markets to enhance margins over the long-term. Tributary ExploraƟon As part of the TransacƟon, certain Mannville-stack exploratory mineral rights in Alberta, prospecƟve thermal heavy oil opportuniƟes at Handel, Saskatchewan and the legacy McCully natural gas producƟon in New Brunswick (collecƟvely, the “Tributary ExploraƟon Assets”), will be transferred from Headwater and Tamarack into Tributary ExploraƟon. In connecƟon with the closing of the TransacƟon and the transfer of the Tributary ExploraƟon Assets, the capitalizaƟon of Tributary ExploraƟon is expected to consist of a total of approximately 237.8 million common shares and 47.6 million share purchase warrants (the “Arrangement Warrants”) with a deﬁned net asset value of $0.42 per share. Under the TransacƟon, Tamarack shareholders will receive approximately 0.33 of a Tributary ExploraƟon share per Tamarack share and Headwater shareholders will receive approximately 0.33 of a Tributary ExploraƟon share per Headwater share and as a result, Tamarack shareholders will own approximately 66.5% and Headwater shareholders will own approximately 33.5% of the total common shares outstanding of Tributary ExploraƟon, with such percentages being equal to their relaƟve ownership of the combined company at closing of the TransacƟon(6). Headwater shareholders will also receive 0.20 of an Arrangement Warrant per Headwater share. Assuming all Arrangement Warrants are exercised by Headwater shareholders, Tamarack shareholders will own approximately 55.4% and Headwater shareholders will own approximately 44.6% of the total common shares outstanding of Tributary ExploraƟon (prior to closing of the Tributary ExploraƟon Private Placement (as deﬁned below)). Each whole Arrangement Warrant will enƟtle the holder to acquire one Tributary ExploraƟon share at an exercise price equal to Tributary ExploraƟon’s deﬁned net asset value of $0.42 per share for a period of 60 days following closing. Following closing of the TransacƟon, it is expected that Tributary ExploraƟon will complete a non-brokered equity private placement ﬁnancing (the “Tributary ExploraƟon Private Placement”) for up to a total of 71.4 million units at a price of $0.42 per unit for aggregate gross proceeds of up to $30 million. The Tributary ExploraƟon Private Placement will be oﬀered to execuƟve oﬃcers, directors and staﬀ of Tributary ExploraƟon. Each unit will consist of one Tributary ExploraƟon common share and one Tributary ExploraƟon purchase warrant with each warrant enƟtling the holder to acquire one common share of Tributary ExploraƟon at an exercise price of $0.42 per share for a period of four years from the issuance date (subject to performance vesƟng thresholds based on the trading price of the Tributary ExploraƟon common shares). Tributary ExploraƟon is expected to be a publicly listed exploraƟon and development company operated by the current management team of Headwater. The Tributary ExploraƟon Assets will be comprised of Headwater’s New Brunswick McCully gas

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asset which has generated an average of $17 million per year in cash ﬂow(1) over the past three winter producing seasons(3), in addiƟon to 168,000 acres of undeveloped Mannville convenƟonal and thermal prospects in Alberta and Saskatchewan. Tributary Exploration net asset value (millions, except per share amounts) At closing Total proved plus probable reserves (NPV10%AT)(4) $ 88.3 Undeveloped land(5) $ 12.4 Total Tributary Exploration net asset value $ 100.7 Total outstanding Tributary Exploration shares(6) 237.8 Net asset value per share(6) $ 0.42 Assuming the closing of the Tributary ExploraƟon Private Placement and the full exercise of the Arrangement Warrants, Tributary ExploraƟon will be well capitalized with approximately $50 million of cash(7) for organic development of current acreage, strategic land sales and acquisiƟons. Tributary ExploraƟon expects to pursue oil weighted assets in western Canada that are rich in organic opportunity and provide stable free cash ﬂow, backstopping the team’s relentless pursuit of shareholder returns. With a proven track record of outsized shareholder returns, precise execuƟon and strong balance sheet stewardship, the Tributary ExploraƟon team, led by Neil Roszell, as ExecuƟve Chair, and Jason Jaskela, as President and Chief ExecuƟve Oﬃcer, is excited for the opportuniƟes ahead. In addiƟon to Mr. Roszell and Mr. Jaskela, the Board of Directors for Tributary ExploraƟon is expected to be comprised of Kevin Olson, Chandra Henry, Steve Larke, Kam Sandhar, and Cheree Stephenson who are all current members of the Headwater Board of Directors. In connecƟon with the TransacƟon, the Tributary ExploraƟon common shares are expected to be consolidated on a ﬁve-to-one basis following the issuance of Tributary ExploraƟon securiƟes pursuant to the TransacƟon and the Tributary ExploraƟon Private Placement. The lisƟng of the Tributary ExploraƟon common shares on a stock exchange will be subject to Tributary ExploraƟon fulﬁlling all the lisƟng requirements of such stock exchange. Timing, Approvals & Governance The TransacƟon will be completed through a plan of arrangement in respect of the shares of Tamarack and Headwater under the Business CorporaƟons Act (Alberta) and is subject to the approval of the TransacƟon by: (i) at least two-thirds of the votes cast by holders of Tamarack common shares and by holders of Headwater common shares; and (ii) a simple majority of the votes cast by holders of Headwater common shares aŌer excluding the votes cast by any holders of Headwater common shares required to be excluded under MulƟlateral Instrument 61-101 - ProtecƟon of Minority Security Holders in Special TransacƟons. The issuance of Tamarack common shares pursuant to the TransacƟon is also subject to the approval of the majority of the votes cast by holders of Tamarack common shares. Closing of the TransacƟon will be subject to approval by the Court of King’s Bench of Alberta as well as other customary closing condiƟons, including the receipt of approval under the CompeƟƟon Act (Canada) and Toronto Stock Exchange (“TSX”) approvals. In addiƟon, the Tributary ExploraƟon Private Placement will require approval by the majority of votes cast by holders of Headwater common shares (aŌer excluding the votes of directors, oﬃcers and staﬀ of Tributary ExploraƟon that are parƟcipaƟng in the Tributary ExploraƟon Private Placement) and Tamarack common shares. An independent commiƩee (the “Independent CommiƩee”) of the Board of Directors of Headwater was formed to consider and review the TransacƟon on behalf of the Headwater Board of Directors. Based on, among other things, the unanimous recommendaƟon of the Independent CommiƩee, the Board of Directors of Headwater unanimously determined, among other things, that the TransacƟon and the entering into of the arrangement agreement are in the best interests of Headwater, the TransacƟon is fair to the Headwater shareholders and approved the arrangement agreement, and has unanimously recommended that Headwater shareholders vote in favor of the resoluƟon to approve the TransacƟon at the special meeƟng of Headwater shareholders expected to be held in November 2026. The Board of Directors of Tamarack unanimously determined that the TransacƟon and the entering into of the arrangement agreement are in the best interests of Tamarack, the TransacƟon exchange raƟo is fair to the Tamarack shareholders and approved the arrangement agreement, and has unanimously recommended that Tamarack shareholders vote in favour of the resoluƟon to approve the TransacƟon and the issuance of Tamarack common shares pursuant to the TransacƟon at the special meeƟng of Tamarack shareholders expected to be held in November 2026. Following closing of the TransacƟon, Tamarack and Tributary ExploraƟon will operate independently and will each conƟnue to be headquartered in Calgary, Alberta. Jason Jaskela, President and Chief ExecuƟve Oﬃcer of Headwater and one other individual nominated by Headwater, and agreed upon by Tamarack, will be appointed to the Board of Directors of Tamarack at closing. All directors and oﬃcers of Headwater, who own approximately 6% of the issued and outstanding common shares of Headwater and all directors and oﬃcers of Tamarack, who own approximately 2% of the issued and outstanding common shares of Tamarack, have entered into support agreements pursuant to which they have agreed to vote in favour of the TransacƟon. At closing, Tamarack will enter into lock-up agreements with certain directors and oﬃcers of Headwater who, following compleƟon of the TransacƟon, will collecƟvely hold or exercise control over approximately 2% of the issued and outstanding Tamarack common shares. Pursuant to the lock-up agreements, each such person will agree not to sell or trade the Tamarack common shares received pursuant to the TransacƟon, except as follows: (i) 1/3 of such Tamarack common shares shall be eligible for disposiƟon

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on the date that is three months aŌer the closing of the TransacƟon; (ii) 1/3 of such Tamarack common shares shall be eligible for disposiƟon on the date that is six months aŌer the closing of the TransacƟon; and (iii) the remaining 1/3 of such Tamarack common shares shall be eligible for disposiƟon on the date that is nine months aŌer the closing of the TransacƟon. A copy of the arrangement agreement will be ﬁled on the SEDAR+ proﬁles of Tamarack and Headwater and will be available for viewing at www.sedarplus.ca. A joint informaƟon circular, which will include details of the TransacƟon, is expected to be mailed to Tamarack and Headwater shareholders in October 2026. Leadership TransiƟon Tamarack is pleased to announce that Steve Buytels, current President of Tamarack, will be promoted to President and Chief ExecuƟve Oﬃcer and join the Board of Directors of the combined company. Mr. Buytels joined Tamarack in March 2020 as Chief Financial Oﬃcer and was promoted to President in July 2025. Tamarack is progressing their CEO transiƟon plan, the culminaƟon of a thorough succession planning process that will posiƟon the combined company for the future. Brian Schmidt, Tamarack’s founding Chief ExecuƟve Oﬃcer since August 2009, will transiƟon to ExecuƟve Chairman of the Board. These appointments are expected to be eﬀecƟve January 1, 2027. Conference Call Tamarack will host a joint webcast with members of the leadership teams of Tamarack and Headwater at 7:30 AM MDT (9:30 AM EDT) on Tuesday, September 8, 2026, to discuss the Transaction. Participants can access the live webcast through links provided on the corporate websites of Tamarack and Headwater . An archive of the webcast will also be made available on the corporate websites of Tamarack and Headwater . New presentations outlining the combination and Tributary Exploration are available on the Tamarack and Headwater websites. Advisors NaƟonal Bank of Canada Capital Markets is acƟng as exclusive ﬁnancial advisor to Tamarack with RBC Capital Markets and CIBC Capital Markets acƟng as strategic advisors and SƟkeman EllioƩ LLP acƟng as legal counsel. NaƟonal Bank of Canada Capital Markets has provided a verbal opinion to the Board of Directors of Tamarack that the exchange raƟo under the arrangement is fair, from a ﬁnancial point of view, to Tamarack, subject to the assumpƟons made and the limitaƟons and qualiﬁcaƟons in the wriƩen opinion of NaƟonal Bank of Canada Capital Markets. For Headwater, Peters & Co. Limited is acƟng as exclusive ﬁnancial advisor to Headwater and Burnet, Duckworth & Palmer LLP is acƟng as legal counsel. Peters & Co. Limited has provided a verbal opinion to the Board of Directors of Headwater that, subject to the assumpƟons made and the limitaƟons and qualiﬁcaƟons contained in the wriƩen opinion, the total consideraƟon to be received by Headwater shareholders pursuant to the TransacƟon is fair, from a ﬁnancial point of view, to Headwater shareholders. In addiƟon, BMO Capital Markets, which was engaged as a ﬁnancial advisor to the Independent CommiƩee, provided a verbal opinion to the Independent CommiƩee that, subject to the assumpƟons made and the limitaƟons and qualiﬁcaƟons contained in the wriƩen opinion, the total consideraƟon to be received by Headwater shareholders pursuant to the TransacƟon is fair, from a ﬁnancial point of view, to Headwater shareholders. About Tamarack Valley Energy Ltd. Tamarack is a corporation engaged in the exploration, development, production and sale of oil and natural gas in the Western Canadian Sedimentary Basin. In 2026, Tamarack transitioned to become a pure-play Clearwater heavy oil producer, currently developing heavy oil positions at Nipisi, Marten Hills and South Clearwater. Tamarack holds an extensive inventory of low-risk, oil development drilling locations and is pursuing enhanced oil recovery upside across its core asset areas. Tamarack is committed to creating long-term value for its shareholders through sustainable free funds flow generation, financial stability and the return of capital. Tamarack is publicly traded on the TSX under the symbol “TVE”. For more information, visit www.tamarackvalley.ca. About Headwater ExploraƟon Inc. Headwater is a Canadian resource company engaged in the exploration for and development and production of petroleum and natural gas in Canada. The majority of Headwater’s heavy oil production and reserves are located in the Clearwater, Grand Rapids and Wabiskaw formations in the greater Marten Hills area of Alberta, while it also has natural gas production and reserves in the McCully field near Sussex, New Brunswick. Headwater is publicly traded on the TSX under the symbol “HWX”. For more information, visit www.headwaterexp.com. For addiƟonal informaƟon, please contact: Brian Schmidt Chief Executive Officer & Founder Tamarack Valley Energy Ltd. Phone: 403.263.4440 www.tamarackvalley.ca Steve Buytels President Tamarack Valley Energy Ltd. Phone: 403.263.4440 www.tamarackvalley.ca Kevin Johnston Chief Financial Officer Tamarack Valley Energy Ltd. Phone: 403.263.4440 www.tamarackvalley.ca Neil Roszell Executive Chair Headwater Exploration Inc. Phone: (587) 391-3680 www.headwaterexp.com Jason Jaskela President & Chief Executive Officer Headwater Exploration Inc. Phone: (587) 391-3680 www.headwaterexp.com Ali Horvath Chief Financial Officer Headwater Exploration Inc. Phone: (587) 391-3680 www.headwaterexp.com

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Reader Advisories This news release consƟtutes a joint news release of Tamarack and Headwater issued in connecƟon with the TransacƟon. Each of Tamarack and Headwater is responsible for the accuracy and completeness of the informaƟon relaƟng to itself, its respecƟve properƟes, operaƟons and securiƟes contained in this news release, and neither party assumes any responsibility for the adequacy or accuracy of informaƟon herein relaƟng solely to the other party. Selected ﬁnancial and operaƟng informaƟon should be read with Tamarack’s and Headwater’s respecƟve unaudited interim consolidated ﬁnancial statements and related management’s discussion and analysis for the period ended June 30, 2026, which are available on SEDAR+ at www.sedarplus.ca and on Tamarack’s website at www.tamarackvalley.ca and Headwater’s website at www.headwaterexp.com. Notes to News Release 1. See “Speciﬁed Financial Measures” . 2. See “Disclosure of Oil and Gas Information” . 3. McCully’s winter producing season is December 1 to April 30th each year . 4. RepresenƟng the net present value of total proved plus probable (“TPP”) reserves discounted at 10% aŌer-tax aƩributed to the Tributary ExploraƟon Assets as evaluated by McDaniel & Associates Consultants Ltd. (“McDaniel”) prepared on September 4, 2026, eﬀecƟve September 1, 2026 (the “Tributary ExploraƟon Reserves Report”). Based on the Tributary ExploraƟon Reserves Report, the net present value of the TPP reserves discounted at 10% before tax is $100.6 million. The evaluaƟon of Tributary ExploraƟon’s properƟes was prepared in accordance with the most recent publicaƟon of the Canadian Oil and Gas EvaluaƟon Handbook (“COGEH”) and NaƟonal Instrument 51-101 – Standards of Disclosure for Oil and Gas AcƟviƟes (“NI 51-101”). The Tributary ExploraƟon Reserves Report uƟlizes forecast prices based on the average of McDaniel, Sproule, ERCE and GLJ Ltd. as at July 1, 2026. 5. RepresenƟng the undeveloped land value aƩributed to the Tributary ExploraƟon Assets including the Mannville-stack exploratory mineral rights in Alberta, prospecƟve thermal heavy oil opportuniƟes at Handel, Saskatchewan as internally esƟmated by management of Headwater. 6. Prior to giving eﬀect to the compleƟon of the Tributary ExploraƟon Private Placement and the exercise of the Arrangement Warrants. 7. Prior to share issuance costs or related fees. Disclosure of Oil and Gas InformaƟon Unless otherwise indicated, the disclosures in this secƟon apply the oil and gas properƟes and acƟviƟes of Tamarack and Headwater and, where expressly indicated, the combined company on a pro forma basis aŌer giving eﬀect to the TransacƟon. Disclosure relaƟng to the Tributary ExploraƟon Assets is based on the respecƟve interests of Tamarack and Headwater in the Tributary ExploraƟon Assets prior to compleƟon of the TransacƟon and the proposed transfer of the Tributary ExploraƟon Assets to Tributary ExploraƟon. Unless otherwise indicated, references to the combined company exclude the Tributary ExploraƟon Assets. Units of measurement For the purpose of calculaƟng unit costs, natural gas volumes have been converted to a boe using a conversion raƟo of six thousand cubic feet of natural gas equal to one barrel of oil unless otherwise stated. A boe conversion raƟo of 6:1 is based upon an energy equivalency conversion method primarily applicable at the burner Ɵp and does not represent equivalency at the wellhead. This conversion conforms with NI 51-101 but may be misleading, parƟcularly if used in isolaƟon. Product types References in this news release to “crude oil” or “oil” refer to light, medium and heavy crude oil product types as deﬁned by NI 51-101. References to “natural gas liquids” throughout this news release comprise pentane, butane, propane, and ethane, being all natural gas liquids as deﬁned by NI 51-101. References to “natural gas” throughout this news release refer to convenƟonal natural gas as deﬁned by NI 51-101. The pro forma run-rate Clearwater producƟon of the combined company (on a boe per day basis) is comprised of approximately 94% crude oil and 6% natural gas and natural gas liquids. Tamarack’s full year 2026 corporate producƟon (on a boe per day basis) is comprised of approximately 88% crude oil, 10% natural gas and 2% natural gas liquids. Corporate decline rate This news release contains metrics commonly used in the oil and natural gas industry, such as corporate decline rate. "Corporate decline rate" represents the percentage decline of Tamarack’s producƟon base, excluding producƟon from new wells drilled in the year, and, where the pro forma combined company’s corporate decline rate is referenced, represents the percentage decline of the combined producƟon base of Tamarack and Headwater on a pro forma basis giving eﬀect to the TransacƟon. Corporate decline rate is not a ﬁnancial measure and does not have a standardized meaning under NI 51-101 or otherwise. This term has been calculated by Tamarack management and may not be comparable to similar measures presented by other companies and, therefore, should not be used to make such comparisons. Management of Tamarack uses this oil and gas metric for its own performance measurements and to provide shareholders with a measure to compare Tamarack’s and, following compleƟon of the TransacƟon, the combined company’s operaƟons over Ɵme. Readers are cauƟoned that the informaƟon provided by this metric should not be relied upon for investment or other purposes. Tamarack’s and, on a pro forma basis, the combined company’s corporate decline rate disclosed in this news release is based on primary and waterﬂood type curves that are internally esƟmated by Tamarack’s and Headwater’s respecƟve management teams and represent esƟmates of the producƟon decline and ulƟmate volumes expected to be recovered from wells over the life of the well. The type curves represent what management believes an average well will achieve, based on methodology that is analogous to wells with similar geological features. Individual well results may be higher or lower than the type curve but management expects that, across a larger number of wells, results will come out to approximately the type curve. Over Ɵme type curves can and will change based on achieving more producƟon history on older wells or more recent compleƟon informaƟon on newer wells. Such type curves are useful in understanding management’s assumpƟons of well performance when making development drilling investment decisions in such areas and assessing the success of the performance of development wells. However, internally prepared type curves do not reﬂect those used by Tamarack’s and Headwater’s respecƟve independent qualiﬁed reserves evaluators in esƟmaƟng their reserves volumes and no reserves have been assigned to such internal type curves. There is no certainty that the combined company will ulƟmately recover the volumes indicated by the internal type curves from the wells it drills. Actual results may vary materially from both the primary and waterﬂood incremental type curve esƟmates. Reserves and Future Net Revenue Disclosures All reserves values, future net revenue and ancillary informaƟon contained in this news release are derived from evaluaƟons by McDaniel prepared in accordance with the deﬁniƟons, standards and procedures contained in the COGEH and NI 51-101 unless otherwise noted. Headwater’s reserves and associated net present value are derived from an independent reserves assessment prepared by McDaniel dated January 15, 2026, evaluaƟng the oil and gas properƟes of Headwater as at December 31, 2025 (the “Headwater Reserves Report”). Tamarack’s reserves and associated net present value are derived from an independent reserves assessment prepared by McDaniel dated January 21, 2026, evaluaƟng the oil and gas properƟes of Tamarack as at December 31, 2025 (the "Tamarack Reserves Report"). Both the Headwater Reserves Report and the Tamarack Reserves Report uƟlize forecast prices based on the average of forecast prices of McDaniel, Sproule ERCE and GLJ Ltd. as at January 1, 2026. See addiƟonal informaƟon above for informaƟon on the Tributary ExploraƟon Reserves Report. All reserve references in this news release are “Company Gross Reserves”. Company Gross reserves are deﬁned as the applicable company’s working interest share of reserves prior to royalty deducƟons. EsƟmates of reserves and future net revenue for individual properƟes may not reﬂect the same level of conﬁdence as esƟmates of reserves and future net revenue for all properƟes, due to the eﬀect of aggregaƟon. There is no assurance that the forecast price and cost assumpƟons applied by McDaniel in evaluaƟng Tamarack’s, Headwater’s or the Tributary ExploraƟon Assets’ reserves, as applicable, will be aƩained and variances could be material. Other than with respect to Headwater’s McCully assets, which are to be transferred to Tributary ExploraƟon, all reserves assigned in the Headwater Reserves Report and the Tamarack Reserves Report are located in the Province of Alberta. For more informaƟon relaƟng to the Headwater Reserves Report and the Tamarack Reserves Report, see the annual informaƟon forms of Headwater and Tamarack for the year ended December 31, 2025, which are available on SEDAR+ at www.sedarplus.ca. AddiƟonal informaƟon relaƟng to the Tributary ExploraƟon Reserves Report will be available in the joint informaƟon circular to be provided to shareholders of Headwater and Tamarack in connecƟon with approval of the TransacƟon.

Page 6

All evaluaƟons and summaries of future net revenue are stated prior to the provision for interest, debt service charges and general and administraƟve expenses and aŌer the deducƟons of royalƟes, operaƟng costs, esƟmated well abandonment and reclamaƟon costs and esƟmated future capital expenditures. It should not be assumed that the esƟmates of future net revenues presented in this news release represent the fair market value of the reserves. The recovery and reserve esƟmates of crude oil, natural gas liquids and natural gas reserves provided herein are esƟmates only and there is no guarantee that the esƟmated reserves will be recovered. Actual crude oil, natural gas and natural gas liquids reserves may be greater than or less than the esƟmates provided herein. There are numerous uncertainƟes inherent in esƟmaƟng quanƟƟes of crude oil, reserves and the future cash ﬂows aƩributed to such reserves. The reserve and associated cash ﬂow informaƟon set forth herein are esƟmates only. Proved reserves are those reserves that can be esƟmated with a high degree of certainty to be recoverable. It is likely that the actual remaining quanƟƟes recovered will exceed the esƟmated proved reserves. Probable reserves are those addiƟonal reserves that are less certain to be recovered than proved reserves. It is equally likely that the actual remaining quanƟƟes recovered will be greater or less than the sum of the esƟmated proved plus probable reserves. Proved developed producing reserves are those reserves that are expected to be recovered from compleƟon intervals open at the Ɵme of the esƟmate. These reserves may be currently producing or, if shut-in, they must have previously been on producƟon, and the date of resumpƟon of producƟon must be known with reasonable certainty. Undeveloped reserves are those reserves expected to be recovered from known accumulaƟons where a signiﬁcant expenditure (e.g., when compared to the cost of drilling a well) is required to render them capable of producƟon. They must fully meet the requirements of the reserves category (proved, probable, possible) to which they are assigned. Certain terms used in this news release but not deﬁned are deﬁned in NI 51-101, CSA Staﬀ NoƟce 51-324 – Revised Glossary to NI 51-101 ("CSA Staﬀ NoƟce 51-324") and/or the COGEH and, unless the context otherwise requires, shall have the same meanings herein as in NI 51-101, CSA Staﬀ NoƟce 51-324 and the COGEH, as the case may be. Drilling LocaƟons Disclosure This news release may disclose Clearwater drilling locaƟons in two categories: (i) booked locaƟons; and (ii) unbooked locaƟons. Booked locaƟons are proved and probable locaƟons derived from either the Headwater Reserves Report or the Tamarack Reserves Report, which were prepared in accordance with NI 51-101 and the COGEH. Unbooked locaƟons do not have aƩributed reserves. Tamarack’s unbooked Clearwater locaƟons have aƩributed conƟngent or prospecƟve resources, based on the resource report prepared by McDaniel, a qualiﬁed independent resource evaluator, eﬀecƟve as of December 31, 2025, in accordance with the deﬁniƟons, standards and procedures contained in NI 51-101 and COGEH. ConƟngent resources are those quanƟƟes of petroleum esƟmated, as of a given date, to be potenƟally recoverable from known accumulaƟons using established technology or technology under development, but which are not currently considered to be commercially recoverable due to one or more conƟngencies. There is uncertainty that it will be commercially viable to produce any porƟon of the conƟngent resources. ProspecƟve resources are those quanƟƟes of petroleum esƟmated, as of a given date, to be potenƟally recoverable from undiscovered accumulaƟons by applicaƟon of future development projects. There is no certainty that any porƟon of the prospecƟve resources will be discovered. If discovered, there is no certainty that it will be commercially viable to produce any porƟon of the prospecƟve resources. Headwater’s unbooked Clearwater locaƟons do not have aƩributed resources. References in this news release to the pro forma combined company’s idenƟﬁed drilling locaƟons (including the greater than 3,000 idenƟﬁed primary drilling locaƟons across the core development areas) represent the aggregate of Tamarack’s and Headwater’s respecƟve drilling locaƟon inventories, on a pro forma basis giving eﬀect to the TransacƟon. Of Tamarack’s Clearwater inventory of >2,000 (net) primary drilling locaƟons, 520 (net) are proved or probable locaƟons, and the remainder are unbooked locaƟons. Of Headwater’s Clearwater inventory of >1,000 (net) primary drilling locaƟons, 273 (net) are proved or probable locaƟons, and the remainder are unbooked locaƟons. Unbooked locaƟons have been idenƟﬁed by management as an esƟmaƟon of the combined company’s mulƟ-year drilling acƟviƟes based on evaluaƟon of applicable geologic, seismic, engineering, producƟon and reserves informaƟon. There is no certainty that the combined company will drill all unbooked drilling locaƟons and if drilled there is no certainty that such locaƟons will result in addiƟonal oil and gas reserves, resources or producƟon. The drilling locaƟons on which the combined company actually drills wells will ulƟmately depend upon the availability of capital, regulatory approvals, seasonal restricƟons, oil and natural gas prices, costs, actual drilling results, addiƟonal reservoir informaƟon that is obtained and other factors. While certain of the unbooked drilling locaƟons have been de-risked by drilling exisƟng wells in relaƟve close proximity to such unbooked drilling locaƟons, the majority of other unbooked drilling locaƟons are farther away from exisƟng wells where management has less informaƟon about the characterisƟcs of the reservoir and therefore there is more uncertainty whether wells will be drilled in such locaƟons and if drilled there is more uncertainty that such wells will result in addiƟonal oil and gas reserves, resources or producƟon. Forward Looking InformaƟon This news release contains certain forward-looking informaƟon relaƟng to Tamarack, Headwater and Tributary ExploraƟon (collecƟvely referred to herein as “forward-looking statements”) within the meaning of applicable Canadian securiƟes laws. Forward-looking statements are oŌen, but not always, idenƟﬁed by the use of words such as “budget”, “guidance”, “outlook”, “anƟcipate”, “target”, “plan”, “conƟnue”, “intend”, “consider”, “esƟmate”, “expect”, “may”, “will”, “should”, “could” or similar words (including negaƟves or grammaƟcal variaƟons) suggesƟng future outcomes. More parƟcularly, this news release contains statements concerning: the business strategy, objecƟves, strength and focus of the combined company, including the characterizaƟon of the combined company as a premier North American oil producer with unparalleled economics; exploraƟon and development plans and strategies of the combined company; the combined company’s ﬁve-year plan and expected Clearwater growth rate; the anƟcipated beneﬁts of the TransacƟon; the anƟcipated Ɵming for compleƟon of the TransacƟon; the terms of the plan of arrangement and closing of the TransacƟon; run-rate producƟon, net (cash) debt and available funding of the combined company; the anƟcipated terms and availability of the combined company’s credit facility; the integraƟon of the businesses, assets, operaƟons, personnel and oﬃces of Tamarack and Headwater; formaƟon of Tributary ExploraƟon and the transfer of the Tributary ExploraƟon Assets to Tributary ExploraƟon; accreƟve metrics of the combined company and expectaƟons of higher total returns to shareholders, including free funds ﬂow per share, corporate decline rates and free funds ﬂow breakeven costs; the amount, Ɵming and realizaƟon of expected synergies of the combined company; various size and scale metrics associated with the combined company, including the depth and quality of drilling inventory; the amount and composiƟon of the combined company’s proved and probable reserves; the business strategy, objecƟves, capitalizaƟon, ﬁnancial posiƟon, operaƟons and development plans of Tributary ExploraƟon; the compleƟon and terms of the Tributary ExploraƟon Private Placement, including the pricing, parƟcipants, size and anƟcipated gross proceeds thereof and the terms, vesƟng condiƟons and potenƟal exercise of the warrants issued pursuant to the Tributary ExploraƟon Private Placement; the number, terms, exercise price, exercise period and potenƟal exercise of the Arrangement Warrants; the anƟcipated proceeds from the exercise of the Arrangement Warrants; the expected capitalizaƟon and cash of Tributary ExploraƟon; the anƟcipated use of Tributary ExploraƟon’s cash to fund organic development, strategic land sales and acquisiƟons; Tributary ExploraƟon’s business strategy and expected pursuit of oil weighted assets in western Canada; the consolidaƟon of Tributary ExploraƟon common shares, including the anƟcipated consolidaƟon raƟo and Ɵming of the consolidaƟon; the anƟcipated dividend increase in the ﬁrst quarter of 2027; the anƟcipated return of capital through dividends and share buybacks; expected balance sheet strength; the exchange raƟo and the number of Tamarack common shares and Tributary ExploraƟon common shares expected to be issued pursuant to the TransacƟon; the relaƟve ownership interests of Tamarack and Headwater shareholders in the combined company and Tributary ExploraƟon following compleƟon of the TransacƟon and, in the case of Tributary ExploraƟon, following the exercise of the Arrangement Warrants and compleƟon of the Tributary ExploraƟon Private Placement; plans for Tributary ExploraƟon to achieve a public lisƟng and expectaƟons regarding future ﬁnancing and issuances of warrants; the terms of lock-up agreements with certain directors and oﬃcers of Headwater; the terms of voƟng support agreements entered into by directors and oﬃcers of Tamarack and Headwater; the saƟsfacƟon of the condiƟons to compleƟon of the TransacƟon, including the receipt of required shareholder, court, regulatory and stock exchange approvals; regulatory and shareholder approvals; board composiƟon of the enƟƟes; Tamarack management changes and the anƟcipated Ɵming thereof; the appointment of Headwater nominees to the Tamarack Board and the anƟcipated management and board composiƟon of Tributary ExploraƟon; revised pro forma producƟon and capital investment guidance; expected producƟon growth rates of the combined company; the Ɵming and amount of anƟcipated capital investments; percentage of pro forma producƟon that is pipe-connected; egress on the Trans Mountain and Prairie Connector pipelines; realizing beneﬁts of enhanced egress out of the WCSB; and execuƟng a disciplined capital management strategy and payment of declared dividends.

Page 7

Future dividend payments and share buybacks, if any, and the level thereof, are uncertain, as the return of capital framework of the combined company and the funds available for such acƟviƟes from Ɵme to Ɵme is dependent upon, among other things, free funds ﬂow ﬁnancial requirements for the combined company’s operaƟons and the execuƟon of its strategy, ﬂuctuaƟons in working capital and the Ɵming and amount of capital expenditures, debt service requirements and other factors beyond the combined company’s control. Further, the ability of the combined company to pay dividends and buyback shares will be subject to applicable laws (including the saƟsfacƟon of the solvency test contained in applicable corporate legislaƟon) and contractual restricƟons contained in the instruments governing its indebtedness, including its credit facility. The amount, Ɵming and frequency of any dividends or share repurchases will be at the discreƟon of the board of directors of the combined company, and there can be no assurance that the combined company will pay dividends or repurchase shares at the levels or on the Ɵmelines currently anƟcipated, or at all. The forward-looking statements contained in this news release are based on certain key expectaƟons and assumpƟons made by Tamarack and Headwater, including those relaƟng to: the business plan of the combined company; execuƟon of the combined company’s 2026 budget; the Ɵming and success of future drilling, conversion, development and compleƟon acƟviƟes; the Ɵming, amount and performance of addiƟonal Clearwater capital investments and secondary waterﬂood recovery iniƟaƟves; the availability of cash on hand, available credit and future anƟcipated adjusted funds ﬂow to fund planned capital development programs and future acquisiƟons, dividends or share buybacks; the geological characterisƟcs of the combined company’s properƟes; prevailing commodity prices, price volaƟlity, price diﬀerenƟals and the actual prices received for the combined company’s products; the realizaƟon of anƟcipated beneﬁts of the combined company’s infrastructure, waterﬂood development program and recent acquisiƟons and divesƟtures; the availability and performance of drilling rigs, faciliƟes, pipelines and other oilﬁeld services; the Ɵming of past operaƟons and acƟviƟes in the planned areas of focus; the performance of new and exisƟng wells; the applicaƟon of exisƟng drilling and fracturing techniques; the combined company’s ability to secure suﬃcient amounts of water; prevailing weather and break-up condiƟons; royalty regimes and exchange rates; the amount and Ɵming of transacƟon, integraƟon and other costs; the anƟcipated tax treatment of the TransacƟon and the transfer of the Tributary ExploraƟon Assets; the realizaƟon of anƟcipated synergies in the amounts and within the Ɵmeframes currently anƟcipated; the impact of inﬂaƟon on costs; the applicaƟon of regulatory and licensing requirements; the conƟnued availability of capital and skilled personnel; the ability to maintain or grow applicable banking faciliƟes; the accuracy of Tamarack’s and Headwater’s geological interpretaƟon of their respecƟve drilling and land opportuniƟes, including the ability of seismic acƟvity to enhance such interpretaƟon; and the combined company’s ability to execute its plans and strategies. In addiƟon, forward-looking statements relaƟng to Headwater are based on certain key expectaƟons and assumpƟons made by Headwater, including those relaƟng to Headwater’s business plan, the Ɵming and success of its future exploraƟon, drilling and development acƟviƟes, the geological characterisƟcs of Headwater’s properƟes and prevailing commodity prices. Forward-looking statements relaƟng to the TransacƟon and the formaƟon, ﬁnancing and proposed public lisƟng of Tributary ExploraƟon are based on the key assumpƟons of Tamarack and Headwater regarding compleƟon of the TransacƟon on the terms and within the Ɵmeframe currently anƟcipated; the saƟsfacƟon of closing condiƟons; the Ɵming and receipt of required regulatory, court, stock exchange and shareholder approvals; the terms of the arrangement agreement; compleƟon of the transfer of the Tributary ExploraƟon Assets to Tributary ExploraƟon; the number of Tamarack common shares, Tributary ExploraƟon common shares and Arrangement Warrants to be issued pursuant to the TransacƟon; the accuracy of the pro forma capitalizaƟon and ownership informaƟon contained in this news release; the number of Arrangement Warrants that will be exercised and the Ɵming of such exercises; the compleƟon of the Tributary ExploraƟon Private Placement on the anƟcipated terms and for the anƟcipated gross proceeds; the ability of Tributary ExploraƟon to fulﬁll the lisƟng requirements of a stock exchange; the expected performance and suﬃciency of the Tributary ExploraƟon Assets to support Tributary ExploraƟon’s business strategy; the ability of Tributary ExploraƟon to execute its business plan and complete strategic land sales and acquisiƟons; the compliance by directors and oﬃcers of Headwater with the terms of the lock-up agreements; and the compliance by directors and oﬃcers of Tamarack and Headwater with the terms of the voƟng support agreements. Although management considers these assumpƟons to be reasonable based on informaƟon currently available, undue reliance should not be placed on the forward-looking statements because Tamarack and Headwater can give no assurances that they may prove to be correct. By their very nature, forward-looking statements are subject to certain risks and uncertainƟes (both general and speciﬁc) that could cause actual events or outcomes to diﬀer materially from those anƟcipated or implied by such forward-looking statements. These risks and uncertainƟes include, but are not limited to: the risk that the TransacƟon is not completed on the anƟcipated terms or within the anƟcipated Ɵming; the risk that the TransacƟon does not result in the anƟcipated beneﬁts; the risk that the businesses, operaƟons and personnel of Tamarack and Headwater are not successfully integrated; the risk that the Tributary ExploraƟon Private Placement is not completed on the anƟcipated terms or at all; the risk that the gross proceeds of the Tributary ExploraƟon Private Placement or the proceeds from the exercise of the Arrangement Warrants are less than anƟcipated; the risk that Tributary ExploraƟon will not have the capitalizaƟon or cash currently anƟcipated; the risk that Tributary ExploraƟon does not achieve a public lisƟng or saƟsfy the lisƟng requirements of a stock exchange; the risk that expected synergies of over $50 million per year are not realized or are delayed; the risk that the lock-up agreements may not be enforceable or that the expiry of lock-up restricƟons results in selling pressure on Tamarack’s common shares; the risk that the funds that the combined company ulƟmately returns to shareholders through dividends and/or share repurchases is less than currently anƟcipated and/or is delayed, whether due to the risks idenƟﬁed herein or otherwise; risks with respect to unplanned third party pipeline outages and risks relaƟng to inclement and severe weather events and natural disasters, such as ﬁre, drought and ﬂooding, including in respect of safety, asset integrity and shuƫng-in producƟon; the risk that future dividend payments are reduced, suspended or cancelled; incorrect assessments of the value of beneﬁts to be obtained from exploraƟon and development programs; that income taxes, general and administraƟve expenses or interest expenses diﬀer materially from expectaƟons; the risk that the combined company may not achieve anƟcipated water injecƟon rates, anƟcipated Clearwater oil producƟon or meet the capital investment guidance; the risk that cash on hand, available credit and anƟcipated adjusted funds ﬂow will not be suﬃcient to fund the combined company’s planned capital programs and any future acquisiƟons, dividends and share buybacks; risks associated with the oil and gas industry in general (e.g. operaƟonal risks in development, exploraƟon and producƟon; and delays or changes in plans with respect to exploraƟon or development projects or capital expenditures); the risk that (i) the U.S. and Canadian governments maintain tariﬀs, increase the rate or scope of tariﬀs, or impose new tariﬀs on the import of goods from one country to the other, including on oil and natural gas, (ii) the U.S. and/or Canada imposes any other form of tax, restricƟon or prohibiƟon on the import or export of products from one country to the other, including on oil and natural gas, and (iii) the tariﬀs imposed by the U.S. on other countries and responses thereto could have a material adverse eﬀect on the Canadian, U.S. and global economies, and by extension the Canadian oil and natural gas industry and the combined company; the risks related to the renegoƟaƟon of the United States-Mexico-Canada Agreement, resulƟng in changes to trade, tariﬀ or market access terms that may adversely aﬀect the combined company or Tributary ExploraƟon; commodity prices, including the impact of the acƟons of OPEC and OPEC+ members; risks relaƟng to reliance on third parƟes, the uncertainty of esƟmates and projecƟons relaƟng to producƟon, cash generaƟon, costs and expenses, including increased operaƟng and capital costs due to inﬂaƟonary pressures; health, safety, liƟgaƟon and environmental risks; access to capital; pandemics; and the risk that the separaƟon of the Tributary ExploraƟon Assets from the combined company may be more complex or costly than anƟcipated. In addiƟon, ongoing military acƟons in Iran and elsewhere in the Middle East and between Russia and Ukraine have the potenƟal to threaten the supply of oil and gas from those regions. The long-term impacts of the acƟons between these naƟons remain uncertain. Due to the nature of the oil and natural gas industry, drilling plans and operaƟonal acƟviƟes may be delayed or modiﬁed to respond to market condiƟons, results of past operaƟons, regulatory approvals or availability of services causing results to be delayed. Please refer to the most recent annual informaƟon form and management’s discussion and analysis of Tamarack for addiƟonal risk factors relaƟng to Tamarack, which can be accessed either on Tamarack’s website at www.tamarackvalley.ca or under Tamarack’s proﬁle on www.sedarplus.ca, and to the most recent annual informaƟon form and management’s discussion and analysis of Headwater for addiƟonal risk factors relaƟng to Headwater, which can be accessed either on Headwater’s website at www.headwaterexp.com or under Headwater’s proﬁle on www.sedarplus.ca. Neither Tamarack nor Headwater assumes any responsibility for the adequacy or accuracy of forward-looking informaƟon relaƟng to the other party contained in this news release. The forward-looking statements contained in this news release are made as of the date hereof and neither Tamarack nor Headwater undertakes any obligaƟon to update publicly or to revise any of the included statements, except as required by law. The forward-looking statements contained herein are qualiﬁed by this cauƟonary statement.

Page 8

This news release contains future-oriented ﬁnancial informaƟon and ﬁnancial outlook informaƟon (collecƟvely, “FOFI”) about free funds ﬂow per share accreƟon, producƟon forecasts, corporate decline rates, free funds ﬂow breakeven costs, net cash, available funding, the expected capitalizaƟon and cash of Tributary ExploraƟon, Tributary ExploraƟon’s anƟcipated future cash ﬂow generaƟon, the anƟcipated gross proceeds of the Tributary ExploraƟon Private Placement and the proceeds from the exercise of the Arrangement Warrants, dividends, share buybacks, debt reducƟon, synergies, balance sheet strength, the revised 2026 capital budget and guidance, and components thereof, including pro forma the compleƟon of the TransacƟon, all of which are subject to the same assumpƟons, risk factors, limitaƟons and qualiﬁcaƟons as set forth in the above paragraphs. FOFI contained in this news release was approved by management of Tamarack and Headwater as of the date of this news release and was provided for the purpose of providing further informaƟon about the combined company’s and Tributary ExploraƟon’s anƟcipated future business operaƟons. Tamarack, Headwater and their respecƟve management believe that FOFI has been prepared on a reasonable basis, reﬂecƟng management’s best esƟmates and judgments, and represents, to the best of management’s knowledge and opinion, the combined company’s and Tributary ExploraƟon’s expected course of acƟon. However, because this informaƟon is highly subjecƟve, it should not be relied on as necessarily indicaƟve of future results. Tamarack and Headwater disclaim any intenƟon or obligaƟon to update or revise any FOFI contained in this news release, whether as a result of new informaƟon, future events or otherwise, unless required pursuant to applicable law. Readers are cauƟoned that the FOFI contained in this news release should not be used for purposes other than for which it is disclosed herein. Changes in commodity prices, diﬀerences in the Ɵming and allocaƟon of capital expenditures, and variances in average producƟon esƟmates can have a signiﬁcant impact on the key performance measures included in the combined company’s and Tributary ExploraƟon’s guidance. Actual results may diﬀer materially from these esƟmates. Speciﬁed Financial Measures This news release includes various speciﬁed ﬁnancial measures, including non-IFRS ﬁnancial measures, non-IFRS ﬁnancial raƟos, capital management measures and supplemental ﬁnancial measures as further described herein. These measures do not have a standardized meaning prescribed by InternaƟonal Financial ReporƟng Standards (“IFRS”) and, therefore, may not be comparable with the calculaƟon of similar measures by other companies. Unless otherwise indicated, the speciﬁed ﬁnancial measures described below are measures used by Tamarack; Headwater may calculate similar measures diﬀerently, and readers should refer to Headwater’s public disclosure record for a descripƟon of any non-IFRS or other speciﬁed ﬁnancial measures used by Headwater . The term “cash ﬂow” used in respect of the Tributary ExploraƟon Assets is a measure used by Headwater and is described separately below. Adjusted funds ﬂow (capital management measure) is deﬁned as cash provided by operaƟng acƟviƟes excluding asset reƟrement obligaƟon expenditures, transacƟon costs and changes in non-cash working capital. Asset reƟrement obligaƟon expenditures and transacƟons costs from business combinaƟons both result from Tamarack’s capital budgeƟng and strategic planning processes, which ﬁrst considers available adjusted funds ﬂow. Asset reƟrement obligaƟon expenditures vary from period to period depending on capital programs, government regulaƟons and the maturity of Tamarack’s operaƟng areas. By also excluding changes in non-cash working capital from cash provided by operaƟng acƟviƟes, the adjusted funds ﬂow measure provides a meaningful metric for Tamarack and others by establishing a clear link between Tamarack’s cash ﬂows, income statement and operaƟng netbacks by isolaƟng the impact of changes in the Ɵming between accrual and cash seƩlement dates, which can oŌen be within management’s control. Tamarack uses adjusted funds ﬂow to assess Tamarack’s ﬁnancial performance and cash generated from operaƟng acƟviƟes. Free funds ﬂow (capital management measure) is deﬁned as adjusted funds ﬂow less investments in oil and natural gas assets (excluding acquisiƟons and disposiƟons) and the seƩlement of asset reƟrement obligaƟons. Management uƟlizes free funds ﬂow to assess how much cash was generated in excess of Tamarack’s capital investment and asset reƟrement programs within the same period, which can be uƟlized to reduce debt, fund acquisiƟons or return capital. Free funds ﬂow is also expressed on per share basis by dividing the measures by the weighted average number of common shares outstanding. Net (cash) debt (capital management measure) is calculated as the sum of Tamarack’s debt, government loans and other, cash, accounts receivable, prepaid expenses and deposits, cross-currency swap liability (asset), assets held for sale (net), accounts payable and accrued liabiliƟes. Tamarack and others uƟlize net (cash) debt to assess liquidity and balance sheet strength by aggregaƟng the select ﬁnancial assets and ﬁnancial liabiliƟes on Tamarack’s balance sheet. Available funding is calculated as the sum of undrawn credit capacity under Tamarack’s credit facility and cash, accounts receivable, prepaid expenses and deposits, cross-currency swap liability (asset), assets held for sale (net), accounts payable and accrued liabiliƟes. Tamarack and others uƟlize available funding to assess the amount of funds that could be available to Tamarack in the near term to fund capital management iniƟaƟves. Sustaining capital (supplementary ﬁnancial measure) represents management’s esƟmate of annual capital investments required to maintain corporate producƟon at prior period levels. This measure allows Management and others to assess the approximate composiƟon of Tamarack’s annual capital investment programs and its corporate ﬁnancial sustainability. Sustaining capital is also uƟlized to calculate Tamarack’s free funds ﬂow breakeven cost. Free funds ﬂow breakeven cost (capital management measure) reﬂects the average minimum WTI price (US per bbl) received by Tamarack where adjusted funds ﬂow net of the base dividend and sustaining capital requirements is approximately equivalent to zero, with sustained current producƟon levels and all other variables held constant. Management believes that free funds ﬂow breakeven provides a useful measure to establish corporate sustainability. The pro forma free funds ﬂow breakeven cost of US$37 per bbl in this news release was based on the following assumpƟons: producƟon of >80,000 boe per day, royalty rate of 13%, operaƟng and transportaƟon expenses of $11.22 per boe, general and administraƟve expenses of $1.11 per boe, sustaining capital requirements of approximately $240 million, WCS basis of (US$12.00 per bbl), AECO price of $2.11 per Mcf, a foreign exchange rate of 1.35 (USD:CAD) and a quarterly dividend of $0.06 per share. Total return to shareholders provides an esƟmate of the total return generated for shareholders on a percentage basis by aggregaƟng certain select metrics consisƟng of producƟon growth, dividends, share buybacks and net debt reducƟon. The return from producƟon growth is calculated as the year-over-year % change in producƟon, dividend growth is based on the yield during year relaƟve to Tamarack’s average market capitalizaƟon, share buybacks is calculaƟng as the number of Tamarack shares purchased in the year divided by Tamarack’s opening common share count and net debt reducƟon is based on the year-over-year net debt decline relaƟve to Tamarack’s average market capitalizaƟon. Please refer to Tamarack’s most recent management’s discussion and analysis for addiƟonal informaƟon relaƟng to speciﬁed ﬁnancial measures including non- IFRS ﬁnancial measures, non-IFRS ﬁnancial raƟos and capital management measures. The management’s discussion and analysis can be accessed either on Tamarack’s website at www.tamarackvalley.ca or under Tamarack’s proﬁle on www.sedarplus.ca. In addiƟon to the speciﬁed ﬁnancial measures used by Tamarack in this news release, the non-IFRS measure “cash ﬂow” is used with respect to Headwater’s McCully gas asset. The most directly comparable ﬁnancial measure to cash ﬂow that is disclosed in Headwater's ﬁnancial statements is "sales". Headwater uses the term cash ﬂow for the purposes of its McCully asset to measure the proﬁtability of such asset before considering any corporate costs. This term may not be comparable to similar measures presented by other companies. Cash ﬂow is calculated as sales, less royalƟes, less blending and transportaƟon, less producƟon expense, inclusive of realized gains (losses) on ﬁnancial derivaƟves. Headwater’s cash ﬂows at a corporate level as reconciled to sales for 2025 is as follows: (i) $618.3 million in sales, less (ii) $104.0 million in royalƟes, less (iii) $70.9 million in blending and transportaƟon, less (iv) $61.3 million in producƟon expense, less (v) $6.5 million ﬁnancial derivaƟve losses, equaling cash ﬂows of $375.6 million. AbbreviaƟons bbl(s) barrel(s) bbls/d barrels per day boe barrels of oil equivalent boe/d barrels of oil equivalent per day WTI West Texas Intermediate, the reference price paid in U.S. dollars at Cushing, Oklahoma for the crude oil standard grade

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