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Cameco is one of the largest global providers of the uranium fuel needed to power a secure energy future.We have interests in tier-one mining and milling operations that have the licensed capacity to produce more than 30 million pounds (our share) of uranium concentrates annually, backed by more than 433 million pounds (our share) of proven and probable mineral reserves. Our operations and projects are diversified by geography and deposit type, backed up by extensive mineral reserves and resources. All of Cameco's operations demonstrate the company's high standards for safety, health and environmental performance.ExpertiseCameco and its predecessor companies have been mining uranium for more than 60 years. We have extensive knowledge of all aspects of uranium mining and are global leaders in exploration, mine engineering, environmental protection, and worker health and safety.Most of Cameco's operating experience is in the Athabasca Basin of northern Saskatchewan, home to the world's largest, high-grade uranium deposits. Mining in this area presents geological, technical and logistical challenges that Cameco has effectively managed using innovative methods such as raise boring and jet boring.Cameco is also a leader in low-cost in situ recovery (ISR) mining. We use ISR methods at our uranium operations in the United States and Kazakhstan.

OverviewCameco's uranium projects are properties that may be developed into uranium-producing operations at some point in the future. The most significant are the Millennium deposit in the Athabasca Basin of Saskatchewan and the Yeelirrie and Kintyre deposits in Australia. Our global exploration activity is adjusted annually in line with market signals and at a pace aligned and Cameco’s mining plans and sourcing needs. In recent years, exploration spending has increased in response to the significant, positive momentum in the nuclear fuel market which has provided a clear signal that more uranium production will be required in the next decade and beyond.Our stage-gate process includes several defined decision points in the assessment and development stages. At each point, we re-evaluate the project based on current economic, competitive, social, legal, political and environmental considerations. If a project continues to meet our criteria, we proceed to the next stage. This process allows us to build a pipeline of projects ready for a production decision and minimize expenditures on projects whose feasibility has not yet been determined. InvestmentsCameco's reputation as an industry leader with expertise in mining and exploration make us an attractive partner for uranium ventures around the world. We lever this position by entering into strategic alliances and joint ventures with other companies that hold high-quality exploration and development projects. Our strategic alliances typically involve investments in publicly listed or private companies with promising exploration lands. In return for these investments, Cameco seeks to obtain rights to expand its ownership to control development of resulting discoveries. Through strategic alliances and joint ventures, we greatly expand the potential return of our investment in uranium exploration and the geographical reach of our technical and financial resources.Millennium The Cree Extension-Millennium project is a Cameco-operated joint venture located in the southeastern portion of Canada's Athabasca Basin. It is approximately 35 km north of Cameco's Key Lake operation.See moreYeelirrie Yeelirrie is one of Australia's largest undeveloped uranium deposits. The deposit is located approximately 650 km northeast of Perth and approximately 750 km south of Cameco's Kintyre project.See moreKintyre Kintyre is an advanced-stage exploration project located at the western edge of the Great Sandy Desert in the East Pilbara region of Australia.See moreExplorationOur exploration program is directed at replacing mineral reserves as they are mined in order to position the company for long-term growth.See more

Cameco is one of the largest global providers of the fuel needed to power a safe, secure energy future.Utilities around the world rely on our nuclear fuel products to generate safe, reliable, emissions-free nuclear power. Together, we are meeting the ever-increasing demand for clean, baseload electricity while delivering energy solutions to support the world's net-zero goals.Cameco's tier-one mining and milling operations have the licensed capacity to produce more than 30 million pounds (our share) of uranium concentrates annually, backed by more than 433 million pounds (our share) of proven and probable mineral reserves. We hold some of the world's most promising uranium projects and invest in ongoing exploration activities. We are also a leading supplier of uranium refining, conversion and fuel manufacturing services. Our ownership interests in Westinghouse and Global Laser Enrichment (GLE) further expand opportunities within the nuclear fuel cycle.Invested in the Nuclear Fuel Cycle Our LocationsOur geographically diverse uranium assets include a large portfolio of low-cost mining operations, extensive mineral reserves and resources, as well as exploration and development projects. 

 2025A Transformational Partnership is announced between Cameco, Brookfield and US Government $80 billion to construct new Westinghouse nuclear power reactorsLong-Term UF6 Supply Agreement signed with Slovenské elektrárneCameco and Orano Sign Historic 15-year Agreement with Indigenous-owned Rise AirCameco Gifts $10 million to USaskCameco joins Net Zero Nuclear as a strategic partner for 20252024Cameco Supports Boreal Healthcare Foundation with $1.5 million DonationCameco Named to TSX30 for 2024SaskPower, Westinghouse and Cameco Sign MOU to Explore Reactor and Fuel Supply Potential2023Net Zero Nuclear Announces Cameco as New Corporate PartnerCameco and Brookfield Complete Acquisition of Westinghouse Electric CompanyCameco Marks Uranium Supply Agreement with China Nuclear International CorporationCameco to Provide UF6 to Support Bulgaria’s Diversification EffortsCameco and Bruce Power Celebrate Extension of Long-Term Arrangements for Nuclear Fuel Through 2040Cameco to Receive Substantial Refund of $300 Million from Canada Revenue AgencyCameco and Energoatom Agree on Commercial Terms to Supply Ukraine’s Full Natural UF6 Needs through 20352022Cameco Produces First Packaged Pounds Following McArthur River/Key Lake RestartCameco Signs Uranium Supply Agreement with China Nuclear International CorporationCameco Announces Closing of US$747.6 Million Bought Deal Offering of Common SharesCameco and Brookfield Renewable Form Strategic Partnership to Acquire Westinghouse Electric CompanyCameco Announces US$650 Million Bought Deal Offering of Common SharesCameco Increases Ownership Stake in Cigar Lake Mine2021Cameco Sells Shares of UEX CorporationCameco Pleased as Supreme Court Dismisses CRA Leave to AppealCameco Increases Interest in Global Laser Enrichment2020Canada Revenue Agency Seeks Leave to Appeal Federal Court of Appeal DecisionCameco Pleased as Federal Court of Appeal Unanimously Upholds Tax Court DecisionMining Association of Canada recognizes Cameco with its “Towards Sustainable Mining” award for extraordinary environmental and community engagement achievementsCanadian Institute of Mining recognizes Cameco’s Cigar Lake Mine with it’s third consecutive John T. Ryan Regional Safety AwardCameco’s $250,000 COVID-19 Relief Fund Supports 35 Community Projects in OntarioCameco Restarting Production at Ontario Operations, Cigar Lake Status UnchangedCameco’s $1 million COVID-19 Relief Fund Supports 67 Community Projects in SaskatchewanCameco Extends Production Suspension at Cigar Lake Mine and Withdraws OutlookCameco Announces Temporary Operational Changes in OntarioCameco Responds to Announcement by KazatompromCameco Suspending Production at Cigar Lake Mine2019Arbitration Tribunal Rules in Favour of Cameco Inc. in TEPCO Contract DisputeCameco Pleased with Section 232 Decision on U.S. Uranium ImportsCameco Step Up for Mental Health raises $400,000 for 21 mental health projects in SaskatchewanCanadian Institute of Mining recognizes Cameco’s Cigar Lake Mine with John T. Ryan Regional Safety AwardTax Court of Canada Releases Decision on Cameco Cost Application2018Canada Revenue Agency appeals Tax Court of Canada decisionTax Court of Canada rules in favour of CamecoCameco suspends production at McArthur River/Key Lake indefinitelyCameco awarded contract for Bruce Power major component projectCameco's Board appoints new ChairJV Inkai Restructuring Takes Effect January 1, 20182017Cameco to suspend production from McArthur River and Key Lake Operations and reduce its dividendLac La Ronge Indian Band and Cameco Sign Collaboration AgreementCameco to Play Key Role in Bruce Power Life Extension ProgramCameco Announces Senior Management Changes and Election of DirectorsCameco Receives 10-year Operating License for Port Hope Conversion Facility from CNSCCameco Rejects TEPCO's Uranium Contract Termination Notice2016Athabasca Basin Communities Renew Partnership with the Uranium Mining IndustryCameco and Kazatomprom Sign Agreement to Restructure JV InkaiCameco Wins Third Consecutive National Mining Safety AwardCameco Announces Operational Changes in Saskatchewan and the United StatesNew Legacy Fund Shares Benefits from Uranium Mining with Northern CommunitiesCameco Named on Top 100 List for most Sustainable Corporations in the World2015Cigar Lake Achieves Production MilestoneCameco and Areva officially mark the grand opening of Cigar Lake on September 23rdCameco achieves commercial production at Cigar LakeMcArthur River recognized for exceptional safety performanceCameco announces contract with India2014Cameco recognized for outstanding safety performance.Cameco ends toll-conversion agreement with Springfields Fuels Ltd.Cameco announces start of ore production at Cigar Lake mine.Cameco announces agreement to sell its interest in Bruce Power.2013Neil McMillan named to succeed Victor J. Zaleschuk as chair of Cameco's board of directors.For the fourth consecutive year, Cameco is recognized as a top Canadian employer with multiple awards.Cigar Lake receives operating licence.Cameco starts production from North Butte uranium mine.2012Cameco announces the completion of the acquisition of the Yeelirrie uranium project in Western Australia.Cameco completes the agreement with AREVA Resources Canada Inc. (AREVA) to purchase AREVA's 27.94% interest in the Millennium project.Cameco announces it has signed an agreement with Advent International to purchase NUKEM Energy GmbH (NUKEM).Cameco announces breakthrough of second shaft at Cigar Lake2011Cameco announces that agreements have been signed with the owners of the Cigar Lake project and McClean Lake mill to process all Cigar Lake ore at McClean Lake.Tim Gitzel is appointed chief executive officer of Cameco.Cameco has signed two agreements to buy uranium produced at the Sotkamo nickel-zinc mine in eastern Finland owned by the Talvivaara Mining Company Plc. (LSE: TALV).2010Cameco signs two key uranium supply agreements with China Guangdong Nuclear Power and China Nuclear Energy Industry Corporation for a total commitment of 52 million pounds of uranium concentrate.Started the main processing plant at the Inkai minesite in Kazakhstan.McArthur River mine was awarded the John T. Ryan National Safety Trophy for the best safety performance in the metal mine category in 2009. The Cigar Lake project was also recognized with a Special Award Certificate for outstanding safety performance in 2009.Cameco has assisted in dismantling thousands of nuclear warheads through the "megatons to megawatts" program.2009Cameco announces completion of Centerra common share sale.Cameco completes its public offering of $500 million principal amount 5.67% Senior Unsecured Debentures, Series D.Cameco receives gross proceeds of approximately $460 million from bought deal public offering of common shares.2008Cameco acquires a 70% interest in the Kintyre uranium exploration project in Western Australia.Cameco enters the enrichment business through an agreement with GE Hitachi Nuclear Energy to acquire a 24% interest in Global Laser Enrichment.2007Cameco forms new strategic alliances with junior uranium companies to maximize opportunities to participate in development of new deposits, including Western Uranium Corporation.Cameco signs a non-binding memorandum of understanding with Kazatomprom to co-operate on the development of uranium conversion capacity and to pursue additional uranium production.2006Cameco acquires a 100% interest in Zircatec Precision Industries, Inc. Zircatec's primary business is manufacturing nuclear fuel bundles and other components for Candu reactors.Cameco's Crow Butte Resources and Smith Ranch-Highland operations both receive ISO 14001:2004 certification.Cameco announces a two-for-one share split.2005Cameco negotiates a toll-processing agreement with British Nuclear Fuels plc (BNFL) to secure 5 million kgU of additional conversion services from BNFL's Springfields plant in the United Kingdom.2004Cameco creates Centerra Gold and consolidates gold assets.Cameco announces development of uranium mine at Inkai, Kazakhstan.Cameco decides to proceed with construction of a new mine at Cigar Lake in northern Saskatchewan.Cameco announces a three-for-one share split and increases its annual cash dividend.2003Cameco receives ISO 14001 Certification for McArthur River and Cigar Lake.Gerald Grandey is appointed chief executive officer of Cameco.Cameco appoints Victor Zaleschuk as the new board chair.2002All of Cameco's common shares are publicly traded after the government of Saskatchewan sells its remaining 10% ownership in February.Cameco increases its stake in Bruce Power to 31.6%.2001Cameco expands its interest in the nuclear industry by acquiring 15% of Bruce Power, the limited partnership formed to lease the Bruce reactors in Ontario.Cameco announces that reserves at McArthur River increased by more than 50%.The McArthur River/Key Lake uranium operations achieve full production of 18 million pounds.2000The McArthur River mine achieves commercial production in November 2000 and becomes the world's largest high-grade uranium mine.1999Cameco signs an agreement for the purchase of natural uranium derived from highly enriched uranium (HEU) contained in dismantled Russian nuclear weapons.Cameco sells a 14% interest in McArthur River and 17% in Key Lake to Cogema Resources Inc. Cameco begins mining at McArthur River, the world's largest high-grade uranium mine.1998Cameco acquires Canadian-based Uranerz Exploration and Mining Limited and Uranerz U.S.A., Inc., increasing its reserves and resources and production levels by about 30%1997Kumtor gold operation in Kyrgyzstan, Central Asia, owned one-third by Cameco, achieves commercial production1996Cameco shares begin trading on the New York Stock ExchangeCameco Gold is formed as a subsidiary of Cameco to conduct the company's gold businessCameco purchases Power Resources, Inc., the largest uranium producer in the United States, increasing its reserves and resources by 10%.1991Cameco completes its initial public offering and shares begin trading on the Toronto and Montreal stock exchanges1990Cameco sells a one-third interest in the Rabbit Lake operation to Uranerz Exploration and Mining Limited in order to reduce debt.1988Cameco is created by the merger of two Crown corporations—Saskatchewan Mining Development Corporation and Eldorado Nuclear Limited. 

Cameco is a prominent supplier of uranium processing services required to produce fuel for the generation of clean electricity. We operate the world's largest commercial refinery in Blind River, have about 18% of the world UF6 primary conversion capacity in Port Hope, and are a leading manufacturer of fuel assemblies and reactor components for CANDU reactors at our facilities in Port Hope and Cobourg.Our focus is on cost-competitiveness and operational efficiency. Our fuel services segment is strategically important because it helps support the growth of the uranium segment. Offering a range of products and services to customers helps us broaden our business relationships and expand our uranium market share.

We are a pure-play investment in the growing demand for nuclear energy, focused on taking advantage of the growth occurring in our industry. We have a proven track record of securely and reliably providing nuclear fuel supplies to a global customer base to generate safe, secure, carbon-free and affordable baseload electricity. Our operations span the nuclear fuel cycle from exploration to fuel services, which include uranium production, refining, UO2 and UF6 conversion services and CANDU fuel manufacturing for heavy water reactors. We have further enhanced our ability to meet growing demand with our investment in Westinghouse Electric Company (Westinghouse) which augments our core business and provides fuel fabrication, maintenance, design and engineering for light water reactors. Our investment in Global Laser Enrichment’s third-generation enrichment technology, if successful, will allow us to participate in the entire nuclear fuel value chain.  

 Global Laser Enrichment LLC (GLE) is the exclusive worldwide licensee of the proprietary Separation of Isotopes by Laser EXcitation (SILEX) laser uranium enrichment technology, a third-generation enrichment technology. Cameco is the commercial lead for the GLE project with a 49% interest and we hold an option to attain a majority interest of 75%. Silex Systems Ltd. (Silex Systems) owns the other 51% interest in GLE and is the licensor of the SILEX laser enrichment technology and the technology lead for GLE.Subject to completion of the technology demonstration program and its progression through to commercialization, GLE has the potential to offer a variety of advantages to the global nuclear energy sector, including:re-enriching depleted uranium tails leftover as a by-product of first-generation gaseous diffusion enrichment operation, repurposing legacy waste into a commercial source of uranium and conversion products to fuel nuclear reactors and aiding in the responsible clean-up of legacy tails inventories, as per GLE’s agreement with the US Department of Energy (DOE);producing commercial low-enriched uranium (LEU) to fuel the world’s existing and future fleet of large-scale light-water reactors (and depending on market developments, SMR’s that also require LEU-based fuel) with greater efficiency and flexibility than current enrichment technologies; andproducing high-assay low-enriched uranium (HALEU), if a market for that fuel stock develops to serve a number of small modular reactor (SMR) and advanced reactor designs that might be commercially deployed and require HALEU-based fuel.Our view is that re-enriching US government inventories of depleted uranium tails into a commercial source of uranium and conversion is GLE’s lowest-risk path to the market. This opportunity is underpinned by an agreement GLE has with the DOE to upgrade depleted uranium tails leftover from DOE’s historic enrichment operations, which may help address the growing supply gap for Western nuclear fuel supplies and services.With the support of both Cameco and Silex Systems, GLE has accelerated its technology demonstration project activities to target an earlier delivery of the successful demonstration of Technology Readiness Level 6 (TRL-6). TRL-6 achievement will confirm large-scale system performance under relevant conditions (pilot-scale demonstration), which represents a major step up in a technology’s demonstrated readiness. Of note, GLE received the second full-scale laser system module from Silex Systems last year, which was installed in GLE’s pilot demonstration facility in the US. GLE’s efforts to bring forward planned activities and expenditures under the technology demonstration program are intended to demonstrate TRL-6 this year. Earlier TRL-6 demonstration may provide optionality for GLE to pursue government and industry support and funding related to potential commercial deployment opportunities (LEU and, potentially, HALEU) that could precede tails re-enrichment if the right conditions exist.Unless another commercial deployment opportunity materializes, GLE will continue its work to complete the technology demonstration project with the potential to deploy its enrichment technology at a commercial scale in Western Kentucky under its agreement with the DOE no later than 2030. GLE’s path to commercialization depends on several factors, including but not limited to the successful progression and completion of GLE’s technology demonstration and maturation program, a clear commercial use case, sound market fundamentals, clarity regarding future Russian fuel imports, the ability to secure substantial government support and funding (specifically, accelerated commercial pathways related to LEU and, potentially, HALEU are reliant on government funding) and long-term industry support.For more information visit www.gle-us.com

With operations on three continents, Cameco is proud to be an active and engaged member of the diverse communities in which we operate.We recognize the importance of sharing timely, local information about our operations, community investments and the opportunities Cameco can provide, with our neighbours around the world.Cameco Australia Australia, home to the world's largest known uranium reserves, is a big part of Cameco's plans for the future. We've been actively exploring for uranium in Australia since 1996 and are involved in several projects across the country, including two of Australia's largest undeveloped uranium deposits, Yeelirrie and Kintyre. Our Australian office is located in metropolitan Perth.Visit Cameco AustraliaCameco Fuel Services Cameco is a major supplier of uranium processing services required to produce fuel for the generation of clean electricity. Our fuel services division has three locations in Ontario: a refinery in Blind River, a conversion facility in Port Hope, and a fuel manufacturing operation with locations in Port Hope and Cobourg.Visit Cameco Fuel ServicesCameco North We're proud to call northern Saskatchewan the home of our largest operations, including our newest mine, Cigar Lake. Our people and partners here, many of whom are local residents, help maintain safe operations, protect the environment and establish strong, healthy community and business relationships.Visit Cameco NorthCameco Resources Cameco Resources is America's largest uranium producer. Our mines in Wyoming and Nebraska use an environmentally friendly in situ recovery mining process where uranium is extracted from wellfields, rather than open pits or underground shafts.Visit Cameco Resources

Proven and Probable As of December 31, 2025(100% basis)(tonnes in thousands; pounds in millions; totals may not add up due to rounding) Proven reservesProbable reservesTotal mineral reservesPropertyTonnesGrade%U3O8Content (lbs U3O8)TonnesGrade%U3O8Content(lbs U3O8)TonnesGrade%U3O8Content(lbs U3O8)Cameco's share of content(lbs U3O8)Metallurgicalrecovery (%)Cigar Lake (UG)263.717.0699.2215.315.4373.2479.016.33172.494.198.9Key Lake (OP)61.10.520.7---61.10.520.70.695.0McArthur River (UG)1,942.06.65284.6484.25.7961.82,426.26.48346.5241.999.2Inkai (ISR)269,017.70.03194.190,674.40.0247.2359,692.20.03241.296.585.0Total271,284.5–578.691,374.0–182.2362,658.5–760.8433.0-NotesUG = underground | OP = open pit | ISR = in situ recoveryNote that the estimates in the above table:use a constant dollar average uranium price of approximately $63 (US) per pound U3O8are based on exchange rates of USD 1.00/CAD 1.28 and 1.00 US/550 Kazakhstan Tengemay not add due to roundingOur estimate of mineral reserves and mineral resources may be positively or negatively affected by the occurrence of one or more of the material risks discussed under the heading Caution about forward-looking information in our 2025 Q4 MD&A, as well as certain property-specific risks. See Uranium - Tier-one operations in our 2025 Q4 MD&A.Metallurgical recoveryWe report mineral reserves as the quantity of contained ore supporting our mining plans and provide an estimate of the metallurgical recovery for each uranium property. The estimate of the amount of valuable product that can be physically recovered by the metallurgical extraction process is obtained by multiplying the quantity of contained metal (content) by the planned metallurgical recovery percentage. The content and our share of uranium in the table above are before accounting for estimated metallurgical recovery.Mineral Reserves and ResourcesOur mineral reserves and resources are the foundation of our company and fundamental to our success.We have interests in a number of uranium properties. The tables in this section show the estimates of the proven and probable mineral reserves, and measured, indicated, and inferred mineral resources at those properties. However, only three of the properties listed in those tables are material uranium properties for us: McArthur River/Key Lake, Cigar Lake and Inkai. Mineral reserves and resources are all reported as of December 31, 2025.We estimate and disclose mineral reserves and resources in five categories, using the definition standards adopted by the Canadian Institute of Mining, Metallurgy and Petroleum Council, and in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (NI 43-101), developed by the Canadian Securities Administrators.  Measured and IndicatedAs of December 31, 2025(100% basis)(tonnes in thousands; pounds in millions; totals may not add up due to rounding) MeasuredIndicatedTotal Measured and IndicatedPropertyTonnesGrade%U3O8Content(lbs U3O8)TonnesGrade%U3O8Content(lbs U3O8)Content(lbs U3O8)Cameco’s Share(lbs U3O8)Cigar Lake82.35.09.1153.85.0717.226.314.3Kintyre   3,897.70.6253.553.553.5McArthur River72.02.283.662.62.223.16.74.7Millennium   1,442.62.3975.975.953.0Rabbit Lake   1,836.50.9538.638.638.6Tamarack   183.84.4217.917.910.3Yeelirrie27,172.90.1695.912,178.30.1232.2128.1128.1Crow Butte1,558.10.196.6939.30.357.213.813.8Gas Hills-Peach687.20.111.73,626.10.1511.613.313.3Inkai75,923.10.0358.263,488.40.0234.592.737.1North Butte-Brown Ranch604.20.081.11,438.40.092.83.93.9Ruby Ranch   2,215.30.084.14.14.1Shirley Basin89.20.160.31,638.20.114.14.44.4Smith Ranch-Highland3,703.50.107.914,372.30.0517.024.924.9Total109,892.5-184.4107,462.3-319.7504.0404.0Note that mineral resources:do not include amounts that have been identified as mineral reservesdo not have a demonstrated economic viabilitytotals may not add due to roundingInferredAs of December 31, 2025(100% basis)(tonnes in thousands; pounds in millions; totals may not add up due to rounding)PropertyTonnesGrade%U3O8Content(lbs U3O8)Cameco’s Share(lbs U3O8)Cigar Lake163.45.5520.010.9Fox Lake386.77.9968.153.3Kintyre517.10.536.06.0McArthur River36.40.532.41.7Millennium412.43.1929.020.2Rabbit Lake2,460.90.6233.733.7Tamarack45.61.021.00.6Crow Butte531.40.161.81.8Gas Hills-Peach3,307.50.086.06.0Inkai33,742.20.0323.38.9North Butte-Brown Ranch294.50.070.40.4Ruby Ranch56.20.140.20.2Shirley Basin508.00.101.11.1Smith Ranch-Highland6,861.00.057.77.7Total49,323.5-201.3153.2Note that mineral resources:do not include amounts that have been identified as mineral reservesdo not have a demonstrated economic viabilitytotals may not add due to roundingAbout mineral resourcesMineral resources do not have to demonstrate economic viability but have reasonable prospects for eventual economic extraction. They fall into three categories: measured, indicated and inferred. Our reported mineral resources are exclusive of mineral reserves.measured and indicated mineral resources can be estimated with sufficient confidence to allow the appropriate application of technical, economic, marketing, legal, and sustainability factors to support evaluation of the economic viability of the depositmeasured resources: we can confirm both geological and grade continuity to support detailed mine planningindicated resources: we can reasonably assume geological and grade continuity to support mine planninginferred mineral resources are estimated using limited geological evidence and sampling information. We do not have enough confidence to evaluate their economic viability in a meaningful way. You should not assume that all or any part of an inferred mineral resource will be upgraded to an indicated or measured mineral resource, but it is reasonably expected that the majority of inferred mineral resources could be upgraded to indicated mineral resources with continued exploration.Our share of uranium in the following mineral resource tables is based on our respective ownership interests. Reported mineral resources have not demonstrated economic viability.About mineral reservesMineral reserves are the economically mineable part of measured and/or indicated mineral resources demonstrated by at least a preliminary feasibility study. The reference point at which mineral reserves are defined is the point where the ore is delivered to the processing plant, except for ISR operations where the reference point is where the mineralization occurs under the existing or planned wellfield patterns. Mineral reserves fall into two categories:proven reserves: the economically mineable part of a measured resource for which at least a preliminary feasibility study demonstrates that, at the time of reporting, economic extraction could be reasonably justified with a high degree of confidenceprobable reserves: the economically mineable part of a measured and/or indicated resource for which at least a preliminary feasibility study demonstrates that, at the time of reporting, economic extraction could be reasonably justified with a degree of confidence lower than that applying to proven reserves For properties where we are the operator, we use current geological models, an average uranium price of $63 (US) per pound U3O8, and current or projected operating costs and mine plans to report our mineral reserves, allowing for dilution and mining losses. We apply our standard data verification process for every estimate. For properties in which we have an interest but are not the operator, we will take reasonable steps to ensure that the reserve and resource estimates that we report are reliable.Our share of uranium in the mineral reserves table below is based on our respective ownership interests.Changes this year Our share of proven and probable mineral reserves decreased from 457 million pounds U3O8 at the end of 2024 to 433 million pounds at the end of 2025. The change was primarily the result of production at Cigar Lake, Inkai and McArthur River, which removed 25 million pounds of proven and probable reserves from our mineral inventory slightly offset by other adjustments based on the mineral reserve estimate updates at Cigar Lake, McArthur River and Inkai.Our share of measured and indicated mineral resources decreased from 408 million pounds U3O8 at the end of 2024 to 404 million pounds at the end of 2025. Our share of inferred mineral resources decreased from 153 million pounds U3O8 to 152 million pounds U3O8. Qualified personsThe technical and scientific information discussed on this page for our material properties (McArthur River/Key Lake, Cigar Lake and Inkai) was approved by the following individuals who are qualified persons for the purposes of NI 43-101:McArthur River/Key LakeGreg Murdock, general manager, McArthur River, CamecoDaley McIntyre, general manager, Key Lake, CamecoAlain D. Renaud, principal resource geologist, technical services, CamecoBiman Bharadwaj, principal metallurgist, technical services, CamecoCigar LakeKirk Lamont, general manager, /Cigar Lake, CamecoScott Bishop, director, technical services, CamecoAlain D. Renaud, principal resource geologist, technical services, CamecoBiman Bharadwaj, principal metallurgist, technical services, CamecoInkaiAlain D. Renaud, principal resource geologist, technical services, CamecoScott Bishop, director, technical services, CamecoBiman Bharadwaj, principal metallurgist, technical services, CamecoSergey Ivanov, deputy director general, technical services, Cameco Kazakhstan LLPImportant information about mineral reserve and resource estimatesAlthough we have carefully prepared and verified the mineral reserve and resource figures in this document, the figures are estimates, based in part on forward-looking information.Estimates are based on knowledge, mining experience, analysis of drilling results, the quality of available data and management’s best judgment. They are, however, imprecise by nature, may change over time, and include many variables and assumptions, including:geological interpretationextraction planscommodity prices and currency exchange ratesrecovery ratesoperating and capital costsThere is no assurance that the indicated levels of uranium will be produced, and we may have to re-estimate our mineral reserves based on actual production experience. Changes in the price of uranium, production costs or recovery rates could make it unprofitable for us to operate or develop a particular site or sites for a period of time. See page 2 of our 2025 Q4 MD&A for information about forward-looking information.Please see our mineral reserves and resources section of our most recent annual information form for the specific assumptions, parameters and methods used for McArthur River, Inkai and Cigar Lake mineral reserve and resource estimates. Important information for US investorsWe present information about mineralization, mineral reserves and resources as required by National Instrument 43-101 – Standards of Disclosure for Mineral Projects of the Canadian Securities Administrators (NI 43-101), in accordance with applicable Canadian securities laws. As a foreign private issuer filing reports with the US Securities and Exchange Commission (SEC) under the Multijurisdictional Disclosure System, we are not required to comply with the SEC’s disclosure requirements relating to mining properties. Investors in the United States should be aware that the disclosure requirements of NI 43-101 are different from those under applicable SEC rules, and the information that we present concerning mineralization, mineral reserves and resources may not be comparable to information made public by companies that comply with the SEC’s reporting and disclosure requirements for mining companies.

Our exploration program is focused on replacing mineral reserves as they are depleted by our production, which is key to sustaining our business, meeting our commitments, and ensuring long-term growth. Our exploration activity is adjusted annually in line with market signals and at a pace aligned with Cameco’s mining plans and marketing requirements. In recent years, as we began to bring back our tier-one production, we also increased exploration spending, all in response to the positive momentum in the nuclear fuel market, which has provided a clear signal that more uranium production will be required in the next decade, setting the stage for a renewed exploration cycle.Our position as one of the world’s largest uranium producers and our continued growth across the nuclear fuel cycle has been driven by decades of experience and our history of exploration, discovery and mining successes. Our land position totals 755,000 hectares (1.8 million acres) that cover exploration and development prospects in Canada, Australia, Kazakhstan and the US that are among the best in the world. In northern Saskatchewan alone, we have direct interests in 660,000 hectares (1.6 million acres) that cover many of the most prospective areas of the Athabasca Basin. Northern SaskatchewanOur well-established infrastructure includes fully licensed and fully permitted uranium mills and mines in the eastern Athabasca basin, along with a supporting network of roads, airstrips and electricity supply.  This not only underpins the potential development of our advanced exploration projects, but also supports:our ongoing work to both delineate existing prospects and deposits,ongoing work to identify undiscovered uranium potentialour decades of work to establish a positive corporate reputation by prioritizing our relationships with northern Saskatchewan Indigenous communities, confirming our long-term commitment to continually engage and provide ongoing benefits to the people that call the region home The well-known uranium endowment of the Athabasca Basin, where we are involved in 41 projects (including partner-operated joint ventures), is the result of its unique geology, creating a remarkable mining jurisdiction that hosts the highest uranium grades and some of the largest uranium deposits in the world. On our projects, numerous uranium occurrences have been identified, along with several prospects and undeveloped deposits of variable grades and sizes which have progressed through multiple stages of evaluation. Depending on the potential deposit size, ore and ground quality, evolving mining technologies and the uranium market environment, some of these prospects are expected to become viable, economic deposits in a uranium market and price environment that supports new primary production and provides an adequate risk-adjusted return. We generally do not provide detailed voluntary disclosure related to ongoing drilling activities, exploration results, discoveries or delineation work unless the information becomes material; with our business activity across the global nuclear fuel and reactor life cycles, our materiality threshold in the exploration context is much higher than most uranium exploration and development companies.

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our production costs are higher than planned, or our cost reduction strategies are unsuccessful, or necessary supplies are not available, or not available on commercially reasonable terms; our estimates of production, purchases, costs, decommissioning, reclamation expenses, or our tax expense prove to be inaccurate; we are unable to enforce our legal rights under our existing agreements, permits or licences; there are defects in, or challenges to, title to our properties; our mineral reserve and resource estimates are not reliable, or there are unexpected or challenging geological, hydrological or mining conditions; we are affected by environmental, safety and regulatory risks, including increased regulatory burdens or delays; necessary permits or approvals from government authorities cannot be obtained or maintained; we are affected by political risks; we are affected by terrorism, sabotage, blockades, civil unrest, social or political activism, accident or a deterioration in political support for, or demand for, nuclear energy; we are impacted by changes in the regulation or public perception of the safety of nuclear power plants, which adversely affect the construction of new plants, the relicensing of existing plants and the demand for uranium; government regulations or policies that adversely affect us, including tax and trade laws and policies; our uranium suppliers fail to fulfil delivery commitments or our uranium purchasers fail to fulfil purchase commitments; our development, mining or production plans are delayed or do not succeed for any reason; Joint Venture Inkai LLP’s (JV Inkai) development, mining or production plans are delayed or do not succeed for any reason; our expectations relating to care and maintenance costs prove to be inaccurate; we are affected by natural phenomena, including inclement weather, fire, flood and earthquakes; our operations are disrupted due to problems with our own or our suppliers’ or customers’ facilities, the unavailability of reagents, equipment, operating parts and supplies critical to production, equipment failure, lack of tailings capacity, labour shortages, labour relations issues, strikes or lockouts, underground floods, cave-ins, ground movements, tailings dam failures, transportation disruptions or accidents, unanticipated consequences of our cost reduction strategies, or other development and operating risks; 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Building a balanced portfolioThe purpose of our contracting framework is to deliver value. Our approach is to secure a solid base of earnings and cash flow by maintaining a balanced contract portfolio that optimizes our realized price.Contracting decisions in all segments of our business need to consider the nuclear fuel market structure, the nature of our competitors, and the current market environment. Most run-rate fuel requirements in our industry are procured under long-term contracts. The spot market is thinly traded, where utilities tend to buy small, discretionary volumes. This market structure is reflective of the baseload nature of nuclear power and the relatively small proportion of the overall operating costs the fuel represents compared to other sources of baseload electricity. Additionally, over two thirds of the fuel supply typically comes from state-owned entities, some of whom have production volume strategies or ambitions to serve state nuclear power programs with low-cost fuel supplies, or from diversified mining companies that produce uranium as a by-product. We evaluate our strategy in the context of our market environment and continue to adjust our actions in accordance with our contracting framework:First, we build a long-term contract portfolio by layering in volumes over time. We will compete for customer demand in the market where we think we can obtain value and, in general, as part of longer-term contracts. Our contracting decisions always factor in who the customer is, our desire for regional diversification, the product form, logistical factors, and our broader corporate strategy. Contracting opportunities may come in various forms and will be additive to our current committed sales.Based on our portfolio of long-term contracts, we decide how to best source material to satisfy that demand, planning our production in accordance with our contract portfolio and other available sources of supply. We dp not plan our production from our tier-one assets to sell in the spot market.We do not intend to build an inventory of excess uranium. Excess inventory contributes to the sense that uranium is abundant and creates an overhang on the market, and it ties up working capital on our balance sheet.Depending on the timing, volume, and certainty of our planned production, purchase commitments, and inventory levels, we may be active buyers in the uranium market as an alternate source of short-, medium- or long-term supply. We generally plan for our annual delivery commitments to slightly exceed the annual supply we expect from our production and long-term purchase commitments, and may undertake spot market purchases to meet our delivery commitments. In general, if we choose to purchase material to meet demand, we expect the cost of that material will be more than offset by the volume of commitments in our sales portfolio that are exposed to market prices over the long term. We may also utilize flexible product loan arrangements to cover short-term supply variability and optimize our overall inventory position.Ultimately, our goal is to protect and extend the value of our contract portfolio on terms that recognize the value of our assets, including future development projects, and achieve pricing mechanisms that provide adequate protection when prices go down and exposure to rising prices. We believe using this framework will allow us to create long-term value. Our focus will continue to be on ensuring we have the financial capacity to execute our strategy and self-manage risk.Long-term contractingUranium is not traded in meaningful quantities on a commodity exchange. Utilities have historically bought the majority of their uranium and fuel services products under long-term contracts that are bilaterally negotiated with suppliers. The spot market is discretionary and typically used for small one-time volumes, not to satisfy annual demand. We sell uranium and fuel products and services directly to nuclear utilities around the world as uranium concentrates, UO2 and UF6, conversion services, or fuel fabrication and reactor components for CANDU heavy water reactors. We have a solid portfolio of long-term sales contracts that reflects our reputation as a proven, reliable supplier of geographically stable supply, and the long-term relationships we have built with our customers.In general, we are active in the market when it is beneficial for us and in support of our long-term contract portfolio. We undertake activity in the spot and term markets prudently, looking at the prices and other business factors to decide whether it is appropriate to participate in the spot or term market. Not only is this activity a source of profit, but it also gives us insight into underlying market fundamentals.We deliver the majority of our uranium under long-term contracts each year, some of which are tied to market-related pricing mechanisms quoted at the time of delivery. Therefore, our net earnings and operating cash flows are generally affected by changes in the uranium price. Market prices are influenced by the fundamentals of supply and demand, market access and trade policy issues, geopolitical events, disruptions in planned supply and demand, and other market factors. The objectives of our contracting strategy are to:optimize realized price by balancing exposure to future market prices while providing some certainty for our future earnings and cash flowretain the flexibility to invest in our assets in step with the ongoing market transitionmaintain a disciplined approach that optimizes the value of our in-ground inventory, based on our view that prevailing industry expectations likely overestimate future supply and underestimate future demandWe have a portfolio of long-term contracts, each bilaterally negotiated with customers, that have a mix of base-escalated pricing and market-related pricing mechanisms, including provisions that provide exposure to rising market prices while also protecting us when the market price is declining. This is a balanced and flexible approach that allows us to adapt to market conditions, put a floor on our average realized price and deliver the best value over the long term.This approach has allowed our realized price to outperform the market during periods of weak uranium demand, and we expect it will enable us to realize increases linked to higher market prices in the future.Base-escalated contracts for uranium: use a pricing mechanism based on a term-price indicator at the time the contract is accepted and escalated to the time of each delivery over the term of the contract.Market-related contracts for uranium: are different from base-escalated contracts in that the pricing mechanism may be based on either the spot price or the long-term price, and that price is generally set a month or more prior to delivery rather than at the time the contract is accepted. These contracts may provide discounts and typically include floor prices and/or ceiling prices, which are established at the time of contract acceptance and usually escalate over the term of the contract.Fuel services contracts: the majority of our fuel services contracts use a base-escalated mechanism per kgU and reflect the market at the time the contract is accepted.Optimizing our contract portfolioWe work with our customers to optimize the value of our contract portfolio. With respect to new contracting activity, there is often a lag from when contracting discussions begin and when contracts are executed. With a value-driven strategy and numerous contracting opportunities in our uranium segment, we continue to be strategically patient inonsidering the commercial terms we are willing to accept. We layer in contracts over time, with higher commitments in the near term and declining over time in anticipation of utilities growing uncovered requirements. Demand may come in the form of off-market negotiations or through on-market requests for proposals. We remain confident that we can add acceptable new sales commitments to our portfolio of long-term contracts to underpin the ongoing operation of our productive capacity and capture long-term value.Given our view that additional long-term supply will need to be incented to meet the growing demand for safe, reliable, carbonfree nuclear energy, our preference today is to sign long-term contracts with market-related pricing mechanisms. However, we believe our customers expect prices to rise and prefer to lock in today’s prices, with a fixed-price mechanism. Our goal is to balance all these factors, along with our desire for customer and regional diversification, with product form, and logistical factors to ensure we have adequate protection and will have exposure to rising market prices under our contract portfolio, while maintaining the benefits that come from having low-cost supply to deliver into a strengthening market.At times, we may also look for opportunities to optimize the value of our portfolio. In cases where there is a changing policy, operating, or economic environment, including the introduction of new taxes or tariffs in certain jurisdictions, we manage risk accordingly. We have taken actions such as positioning material ahead of expected deliveries, revising our contract terms to protect us from unexpected future implementation of taxes or tariffs, and adjusting our contracts to minimize potential negative impacts while maintaining strong customer relationships, and we will continue to consider additional mitigation in the future.