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Cameco (TSX: CCO; NYSE: CCJ) has signed a uranium supply agreement with China Nuclear International Corporation, a subsidiary of China National Nuclear Corporation (CNNC), one of the country's largest nuclear power operators.

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

Community leaders from across northern Saskatchewan, Cameco, and AREVA Resources Canada Inc. have established a legacy trust fund that will provide funding for community projects for decades to come.

Cameco (TSX: CCO; NYSE: CCJ) announced that it has signed a uranium supply agreement with the China Nuclear International Corporation, a subsidiary of the China National Nuclear Corporation (CNNC), one of the country's largest nuclear power operators.

Learn how uranium is mined, milled and processed at CamecoIn Uranium Part 1 - watch how uranium is mined and milled at our northern Saskatchewan operations.Watch Uranium Part 2 - Uranium ProcessingVideo courtesy of How It's Made, a Discovery Communications, Science Channel program

Saskatoon, Saskatchewan, Canada, March 2, 2026 All amounts in Canadian dollars unless specified otherwiseCameco (TSX: CCO; NYSE: CCJ) has entered a long-term agreement to supply uranium ore concentrate (U3O8) to the Government of India’s Department of Atomic Energy, for use in the country’s fleet of nuclear reactors. The agreement will see Cameco supply nearly 22 million pounds of uranium ore concentrate to India over a nine-year period on market-related price terms, with a total contract value estimated at approximately $2.6 billion. India currently has 24 operating reactors along with ambitious plans to deploy dozens more to reach 100 GW by 2047. Deliveries under the contract are expected to begin in 2027 and run through 2035 in alignment with Cameco’s long-term contracting strategy. The volumes under this contract were included in the total long-term contracting volumes and in the expected five-year realized uranium price sensitivity analysis, disclosed in the 2025 annual Management’s Discussion and Analysis in February 2026. Cameco’s CEO Tim Gitzel attended an event in Delhi today to celebrate the agreement alongside Indian Prime Minister Narendra Modi, Canadian Prime Minister Mark Carney and Saskatchewan Premier Scott Moe, highlighting the strong diplomatic and commercial trade relationships between the countries. “Cameco is proud to be a strategic partner with India to help meet its civil nuclear fuel needs and support its trade relationship with Canada,” said Gitzel. “India is embarking on an ambitious nuclear expansion to power its development plans and meet the future energy security needs of its people. That isn’t possible without a stable supply of uranium fuel. Importantly, this demand underscores an emerging trend of sovereign buyers locking up large volumes from multiple suppliers, and in a window where demand continues to grow and available supplies continue to become more uncertain and constrained. As a proven and reliable producer, Cameco is globally recognized as a nuclear fuel supplier of choice, and we are pleased to be a trusted provider for India once again.” Cameco previously supplied uranium to India under a five-year contract that began in 2015. At the time of this news release, the estimated value of the new contract is approximately $2.6 billion based on a uranium price of US$86.95 per pound, which was the average of the month-end UxC and TradeTech uranium spot prices on February 28, 2026, and the exchange rate on February 27, 2026 of USD1.00/CAD1.36. Further details of the newly signed contract are commercially sensitive and confidential. Forward Looking Information This news release includes statements and information about expectations for the future, which are referred to as forward-looking information. This forward-looking information is based on current views, which can change significantly, and actual results and events may be significantly different from what is currently expected. Examples of forward-looking information in this news release include: the expected volume of uranium ore concentrate to be supplied, the period over which it is to be supplied and the estimated total contract value; the anticipated beginning and ending dates for deliveries; India’s future plans for deployment of additional reactors and nuclear expansion to meet future energy needs, and the expectation that demand continues to grow and available supplies will continue to become more uncertain and constrained. Material risks that could lead to different results include the risk that delivery obligations under the agreement are not fully satisfied, or are delayed, for unexpected reasons; the risk that prevailing pricing terms at time of delivery do not result in the full amount of the estimated contract value; the risk that India’s future deployment and expansion plans may be impeded or delayed for any reason, and the risk that there is not continued growth in demand. In presenting the forward-looking information, we have made material assumptions which may prove incorrect about our ability to satisfy our delivery obligations fully in a timely manner, future uranium prices and India’s successful implementation of its plans. About Cameco Cameco is one of the largest global providers of the uranium fuel needed to power a secure energy future. Our competitive position is based on our controlling ownership of the world’s largest high-grade reserves and low-cost operations, as well as significant investments across the nuclear fuel cycle, including ownership interests in Westinghouse Electric Company and Global Laser Enrichment. Utilities around the world rely on Cameco to provide global nuclear fuel solutions for the generation of safe, reliable, carbon-free nuclear power. Our shares trade on the Toronto and New York stock exchanges. Our head office is in Saskatoon, Saskatchewan, Canada. As used in this news release, the terms we, us, our, the Company and Cameco mean Cameco Corporation and its subsidiaries unless otherwise indicated. Investor inquiries Cory Kos 306-716-6782 cory_kos@cameco.com Media inquiries Veronica Baker 306-385-5541 veronica_baker@cameco.com

 As 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 roundingMineral 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.  About 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, Cameco​Biman 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.

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.

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.