Cameco: 2025 Annual Information Form

2025 Annual information form

March 19, 2026

Contents

Important information about this document 3

Our business 9

Our values and strategy 14

Operations, projects and investments 29

Uranium - Tier-one operations 30

Uranium - Tier-two operations 80

Uranium - Advanced projects 81

Uranium - Exploration 83

Fuel services 85

Westinghouse Electric Company 88

Other nuclear fuel cycle investments 94

Mineral reserves and resources 95

Our sustainability principles and practices 101

The regulatory environment 104

Risks that can affect our business 114

1. - Strategic risks 115

2. - Financial risks 120

3. - Regulatory and governance risks 126

4. - Operational risks 133

Legal proceedings 141

Investor information 141

Governance 147

Appendix A 152

‌Important information about this document

This annual information form (AIF) for the year ended December 31, 2025, provides important information about Cameco Corporation. It describes our history, our markets, our operations and projects, our mineral reserves and resources, our approach to sustainability matters, our regulatory environment, the risks we face in our business and the market for our shares, among other things.

It also incorporates by reference:

• our management's discussion and analysis for the year ended December 31, 2025 (2025 MD&A), which is available on SEDAR+ (https://www.sedarplus.ca) and on EDGAR (https://www.sec.gov) as an exhibit to our Annual Report on Form 40-F; and

• our audited consolidated financial statements for the year ended December 31, 2025 (2025 financial statements), which are also available on SEDAR+ and on EDGAR as an exhibit to our Annual Report on Form 40-F.

  We have prepared this document to meet the requirements of Canadian securities laws, which are different from what United States (US) securities laws require.

  The information contained in this AIF is presented as at December 31, 2025, the last day of our most recently completed financial year, and is based on what we knew as of March 17, 2026, except as otherwise stated.

  Reporting currency and financial information

  Unless we have specified otherwise, all dollar amounts are in Canadian dollars. Any references to US$ mean US dollars.

  The financial information in this AIF has been presented in accordance with International Financial Reporting Standards (IFRS).

  Caution about forward-looking information

  Our AIF and the documents incorporated by reference include statements and information about our expectations for the future. When we discuss our strategy, plans and future financial and operating performance, or other things that have not yet taken place, we are making statements considered to be forward-looking information or forward-looking statements under Canadian and US securities laws. We refer to them in this AIF as forward-looking information. In particular, the discussions under the headings Market overview and developments, Building a balanced portfolio, and Westinghouse Electric Company in this AIF contain forward-looking information.

  Key things to understand about the forward-looking information in this AIF:

• It typically includes words and phrases about the future, such as anticipate, believe, estimate, expect, plan, will, intend, goal, target, forecast, project, strategy and outlook (see examples on page 4).

• It represents our current views and can change significantly.

• It is based on a number of material assumptions, including those we have listed below on pages 7 and 8, which may prove to be incorrect.

• Actual results and events may be significantly different from what we currently expect, due to the risks associated with our business. We list a number of these material risks below. We recommend you also review other parts of this document, including Risks that can affect our business starting on page 114, and our 2025 MD&A, which includes a discussion of other material risks that could cause actual results to differ significantly from our current expectations.

  Forward-looking information is designed to help you understand management's current views of our near- and longer-term prospects, and it may not be appropriate for other purposes. We will not necessarily update this information unless we are required to by Canadian or US securities laws.

  Examples of forward-looking information in this AIF

• our expectations about 2026 and future global uranium supply, consumption, contracting, demand, geopolitical issues and the market, including the discussion under the headings Market overview and developments and Building a balanced portfolio

• the discussion under the heading Our strategy, including the role of nuclear energy in the world's shift to a

  low-carbon, climate-resilient economy, our expectation that our strategy will allow us to increase long-term value, our intention to execute our strategy with an emphasis on safety, people and the environment, our ability to address risks and opportunities that we believe may have a significant impact on our ability to add long-term value for our stakeholders, and our expected financial capacity to execute our strategy, invest in new opportunities and

  self-manage risk

• the discussion of our expectations relating to our 49% interest in Westinghouse Electric Company (Westinghouse), including our investment expanding our participation in the nuclear fuel value chain and providing a platform for further growth and various factors and drivers for Westinghouse's business segments

• our expectations relating to our Canada Revenue Agency (CRA) transfer pricing dispute, including our confidence that the courts would reject any attempt by CRA to utilize the same or similar positions for other tax years currently in dispute, and our belief that CRA should return the full amount of cash and security that has been paid or otherwise secured by us

• our view that we have the strengths to take advantage of the world's rising demand for safe, secure, reliable, affordable, and carbon-free energy

• our belief that we have the right strategy to add long-term value, and our ability to do so in a manner that reflects our values

• that we will continue to focus on delivering our products responsibly and addressing the sustainability risks and opportunities that we believe will make our business sustainable and will build long-term value

• our expectations about 2026 and future consumption of conversion services

• our expectations for the future of the nuclear industry and the potential for new enrichment technology, including that nuclear power must be a central part of the solution to the world's shift to a low-carbon, secure energy economy while helping provide energy security and that our investment in enrichment technology, if successful, will allow us to participate in the entire nuclear fuel value chain

• our expectations relating to care and maintenance costs

• our expectations of executing major supply contracts

• our ability to capitalize on the current backlog of

  long-term contracting as a proven and reliable supplier with tier-one productive capacity and a record of honouring supply commitments, and to increase value throughout these price cycles

• future plans and expectations for our uranium properties, advanced projects, and fuel services operating sites, including production levels and the suspension of production at certain properties, pace of advancement and expansion capacity, and carbon reduction targets

• estimates of operating and capital costs and mine life for our tier-one uranium operations

• our expectations regarding our licence for Crow Butte

• our ability to successfully negotiate a new collective agreement for the unionized employees at McArthur River

• estimated decommissioning and reclamation costs for uranium properties and fuel services operating sites

• Kazatomprom's planned production levels for JV Inkai and the timing of deliveries, and our other expectations regarding JV Inkai, including the impact of the new Mineral Extraction Tax (MET) on JV Inkai's cost structure

• our mineral reserve and resource estimates

• our expectations that the price of uranium, production costs, and recovery rates will allow us to operate or develop a particular site or sites

• estimates of metallurgical recovery and other production parameters for each uranium property

• production estimates at the McArthur River/Key Lake, Cigar Lake and JV Inkai operations, and fuel services

• our discussion of the ongoing conflict between Russia and Ukraine

• our views on our ability to align our production with market opportunities and our contract portfolio, and the factors that may affect our cash production costs

• our expectation regarding opportunities to improve operational effectiveness and to reduce our impact on the environment, including through the use of digital and automation technologies

• our expectations about when future reactors will come online

• our efforts to explore emerging opportunities within the nuclear power value chain which contribute to decarbonization, and help provide secure and affordable energy

• our expectations about future demand for small modular reactors (SMR)

• the discussion under the heading Our Sustainability principles and practices, including our belief that we can be part of the solution to enhance national energy and climate security and our position to deliver significant longterm business value

  Material risks

• actual sales volumes or market prices for any of our products or services are lower than we expect, or cost of sales is higher than we expect, for any reason, including changes in market prices, loss of market share to a competitor, tariffs, trade restrictions or geopolitical issues

• we are adversely affected by changes in currency exchange rates, interest rates, royalty rates, tax rates, tariffs, or inflation

• our production costs are higher than planned, or affected by unexpected factors, or necessary supplies are not available or not available on commercially reasonable terms

• our strategies may change, be unsuccessful or have unanticipated consequences, or we may not be able to achieve anticipated operational flexibility and efficiency

• changing views of governments regarding the pursuit of carbon reduction strategies or that our view on the role of nuclear power in pursuit of those strategies may prove to be inaccurate

• our estimates and forecasts prove to be inaccurate, including production, purchases, deliveries, cash flow, revenue, costs, decommissioning, reclamation expenses, or timing or receipt of future dividends from JV Inkai

• that we may not realize the expected benefits from our investment in Westinghouse or any of our other joint venture investments

• that Westinghouse fails to generate sufficient cash flow to fund its approved annual operating budget or make distributions to the partners

• we are unable to enforce our legal rights under our existing agreements, permits or licences

• we are subject to litigation or arbitration that has an adverse outcome

• that the courts may accept the same, similar or different positions and arguments advanced by CRA to reach decisions that are adverse to us for other tax years currently in dispute

• the possibility of a materially different outcome in disputes with CRA for other tax years

• our expectation that the US Department of Energy (DOE) will make available a portion of its excess uranium inventory over the next two decades

• our ability to implement and execute our overarching low carbon transition strategy

• our investments allowing us to participate in the entire nuclear fuel value chain; fuel fabrication; reactor maintenance; development of new reactors; and nuclear sustainability services

• our expectations regarding Global Laser Enrichment LLC's (GLE) path to commercialization

• the risk that we and Westinghouse may not be able to meet sales commitments for any reason

• the risk that Westinghouse may not achieve the expected growth in its business

• the risk to Westinghouse's business associated with potential production disruptions, including those related to global supply chain disruptions, global economic uncertainty, political volatility, labour relations issues, and operating risks

• the risk that Westinghouse may not be able to implement its business objectives in a manner consistent with its or our sustainability principles and practices and other values

• the risk that Westinghouse's strategies may change, be unsuccessful, or have unanticipated consequences

• the risk that Westinghouse may be unsuccessful in respect of its new business initiatives, including its participation in the construction of two nuclear reactors at the Dukovany power plant in the Czech Republic, and the realization of the expected benefits of the strategic partnership with the US Government intended to accelerate the deployment of Westinghouse nuclear reactors in the US and globally

• the risk that Westinghouse may fail to comply with nuclear licence and quality assurance requirements at its facilities

• the risk that Westinghouse may lose protections against liability for nuclear damage, including discontinuation of global nuclear liability regimes and indemnities

• the risk that increased trade barriers may adversely impact our business, or the business of any of the joint ventures in which we have invested

• the risk that Westinghouse may default under its credit facilities, impacting adversely Westinghouse's ability to fund its ongoing operations and to make distributions

• the risk that liabilities at Westinghouse may exceed our estimates and the discovery of unknown or undisclosed liabilities

• that CRA does not agree that the court rulings for the years that have been resolved in Cameco's favour should apply to subsequent tax years

• that CRA will not return all or substantially all of the cash and security that has been paid or otherwise secured in a timely manner, or at all

• 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 factors (such as climate change), safety and regulatory risks, including workforce health and safety or increased regulatory burdens or delays

• necessary permits or approvals from government authorities cannot be obtained or maintained

• we are affected by political risks, including developments in US foreign policy, global conflicts, sanctions, or any potential future unrest in Kazakhstan

• we may be affected by crime, corruption, the making of improper payments or the provision of benefits that may violate Canadian or US laws relating to foreign corrupt practices or sanctions

• we are affected by war, terrorism, cyber-attacks, sabotage, blockades, civil unrest, social or political activism, outbreak of illness (such as a pandemic), accident or a deterioration in political support for, or demand for, nuclear energy

• operations are disrupted due to problems with our own or our joint venture partners', suppliers' or customers' facilities, the unavailability or delayed delivery of reagents, equipment, operating parts and supplies critical to production, equipment failure, lack of tailings capacity, labour shortages, labour relations issues, strikes or lockouts, fires, underground floods, cave-ins, ground movements, tailings dam failures, transportation disruptions or accidents, aging infrastructure, or other development and operating risks

• the inability of Westinghouse and the US Government to enter into definitive agreements relating to the strategic partnership between Cameco, Brookfield and the US Government or to effect their future obligations related to the transactions contemplated by the strategic partnership

• the unavailability of US Government funding and support for the transactions contemplated by the strategic partnership, including the ability of the executive branch of the US Government to obtain funding and support via the appropriations process or from other sources

• the risk that occupational health and safety issues may arise at Westinghouse's operations

• the risk that there may be disputes between us and Brookfield Renewable Partners and its institutional partners (collectively, with Brookfield Asset Management, "Brookfield") regarding our strategic partnership, or disputes between us and any of our other joint venture partners

• the risk that we may default under the governance agreement with Brookfield, including us losing some or all of our interest in Westinghouse

• disruption or delay in the transportation of our products

• a major accident at a nuclear power plant

• 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 laws, regulations, policies or decisions that adversely affect us, including tax and trade laws, tariffs and sanctions, including changes in mining laws or regulations

• our uranium suppliers or purchasers fail to fulfil their commitments

• our McArthur River development, mining or production plans, including the planned transition into two new mine areas within zone 1 and the zone 4 clay area, are delayed or do not succeed for any reason, including unforeseen challenges during the development of these areas

• our Cigar Lake development, mining or production plans are delayed or do not succeed for any reason

• the risk that the planned infrastructure installations and repairs at the Key Lake mill during the extended 2026 maintenance shutdown may not proceed as scheduled, or may encounter unforeseen delays, reducing operational capacity and expected production levels

• JV Inkai's development, mining or production plans are delayed or do not succeed for any reason or JV Inkai is unable to transport and deliver its production, or its production cost structure is impacted by the new MET more adversely than we expect

• our production plan for our fuel services division is delayed or does not succeed for any reason

• our expectations relating to care and maintenance costs prove to be inaccurate

• we are affected by natural phenomena, such as forest fires, floods or earthquakes as well as shifts in temperature, precipitation, and the impact of more frequent severe weather conditions on our operations as a result of climate change

• following the execution of definitive transaction documents by Westinghouse and the US Government, the determination by the legislative, judicial or executive branches of the US federal or any US state government that any future funding commitments or other aspect of the transactions contemplated by the strategic partnership was or is not in compliance with law

  Material assumptions

• our expectations regarding sales and purchase volumes and prices for uranium and fuel services, cost of sales, trade restrictions, inflation, and that counterparties to our sales and purchase agreements will honour their commitments

• our expectations for the nuclear industry, including its growth profile, market conditions, geopolitical issues, and the demand for and supply of uranium

• the continuing pursuit of carbon reduction and energy security strategies by governments and the role of nuclear in the pursuit of those strategies

• the success of our plans and strategies relating to our investment in Westinghouse and our other joint venture investments

• our cost expectations, including production costs and the factors affecting them, operating costs, and capital costs

• our expectations regarding tax payments, tax rates, tariffs, royalty rates, currency exchange rates, interest rates and inflation

• that courts will reach consistent decisions for other tax years that are based upon similar positions and arguments, in our dispute with CRA

• that CRA will not successfully advance different positions and arguments that may lead to different outcomes for other tax years

• our expectation that we will recover all or substantially all of the amounts paid or secured in respect of the CRA dispute to date

• our expectations regarding spot prices and realized prices for uranium

• our decommissioning and reclamation estimates, including the assumptions upon which they are based, are reliable

• our mineral reserve and resource estimates, and the assumptions upon which they are based, are reliable

• our understanding of the geological, hydrological and other conditions at our uranium properties

• Westinghouse's ability to generate cash flow and fund its approved annual operating budget and make distributions to the partners

  • the risks that generally apply to all our operations and advanced uranium projects that are discussed under the heading Risks that can affect our business in this AIF and under the heading Managing the risks in our 2025 MD&A

  • our dependence, in part, on government contracts, which may only be partially funded, subject to termination, heavily regulated and audited.

• that the construction of new nuclear power plants and the relicensing of existing nuclear power plants will not be adversely affected by changes in regulation or in the public perception of the safety of nuclear power plants

• our ability to continue to supply our products and services in the expected quantities and at the expected times

• our expected production levels for Cigar Lake, McArthur River/Key Lake, JV Inkai and our fuel services operating sites

• plans to transport our products succeed, including the shipment of our share of JV Inkai production to our Blind River refinery

• our ability to mitigate adverse consequences of production shortfalls or delays in the shipment of our share of

  JV Inkai production to our Blind River refinery

• our ability to compete for additional business opportunities so as to generate additional revenue for us as a result of our investment in Westinghouse

• market conditions and other factors upon which we based our investment in Westinghouse and our related forecasts will be as expected

• Westinghouse's production, purchases, sales, deliveries, and costs

• Westinghouse's ability to mitigate adverse consequences of delays in production and construction

• the success of Westinghouse's plans and strategies including its participation in the construction of two nuclear reactors at the Dukovany power plant in the Czech Republic, and the strategic partnership with the US Government intended to accelerate the deployment of Westinghouse nuclear reactors in the US and globally

• the absence of new and adverse laws, government regulations, policies or decisions in any country where such developments would affect us, including with respect to changes in mining laws or regulations

• that there will not be any significant adverse consequences to Westinghouse's business resulting from business disruptions, including those relating to supply disruptions, economic or political uncertainty and volatility, labour relation issues, and operating risks

• Westinghouse will comply with the covenants in its credit agreement

• our Key Lake mill production plans succeed, and that the planned infrastructure installations and repairs at Key Lake during the extended 2026 maintenance shutdown proceed and are completed as scheduled

• the McClean Lake mill is able to process Cigar Lake ore as expected

• our Cigar Lake and McArthur River development, mining and production plans succeed, and the planned transition into two new mine areas within zone 1 and the zone 4 clay area at McArthur River does not encounter unforeseen challenges during the development of these areas

• JV Inkai's development, mining and production plans succeed, and that JV Inkai will be able to deliver its production, and that its production cost structure is not more adversely impacted by the new MET than we expect

• the ability of JV Inkai to pay dividends, or the timing of their payments

• that care and maintenance costs will be as expected

• our and our contractors' ability to comply with current and future environmental, safety and other regulatory requirements, and to obtain and maintain required regulatory approvals

• that we will be successful in our efforts to renew our operating licence for Crow Butte

• our operations and those of our joint venture investments are not significantly disrupted as a result of political instability, sanctions, nationalization, developments in US foreign policy, terrorism, sabotage, blockades, civil unrest, breakdown, natural disasters, environmental factors (including climate change), outbreak of illness (such as a pandemic), governmental or political actions, litigation or arbitration proceedings, the unavailability of reagents, equipment, operating parts and supplies critical to production, labour shortages, labour relations issues, strikes or lockouts, underground floods, cave-ins, ground movements, tailings dam failure, lack of tailings capacity, transportation disruptions or accidents, aging infrastructure or other development or operating risks

• that no major accident at a nuclear power plant will occur

• Westinghouse will comply with nuclear licence and quality assurance requirements at its facilities

• Westinghouse maintaining protections against liability for nuclear damage, including continuation of global nuclear liability regimes and indemnities

• the ability of Westinghouse and the US Government to enter into definitive agreements relating to the strategic partnership between Cameco, Brookfield and the US Government and their ability to meet their obligations under them

• the availability of US Government funding and support for the transactions contemplated by the strategic partnership, including the ability of the executive branch of the US Government to obtain funding and support via the appropriations process or from other sources

• the assumption that following the execution of definitive transaction documents by Westinghouse and the US Government, none of the legislative, judicial or executive branches of the US federal or any US state government will determine that any future funding commitments or other aspect of the transactions contemplated by the strategic partnership was or is not in compliance with law

  ‌Our business

  Cameco Corporation 2121 - 11th Street West Saskatoon, Saskatchewan Canada S7M 1J3 Telephone: 306.956.6200

  This is our head office, registered office and principal place of business.

  We are publicly listed on the Toronto and New York stock exchanges, and had a total of 3,082 employees at December 31, 2025.

Our operations span the nuclear fuel cycle from exploration to fuel services, which include uranium production, refining, uranium dioxide (UO2) and uranium hexafluoride (UF6) conversion services and CANDU fuel manufacturing for heavy water reactors. We have further enhanced our ability to meet our customers' growing demand for reliable and secure nuclear fuel supplies, services and technologies with our investments in Westinghouse, augmenting the core of our business and providing fuel fabrication, design and engineering for light water reactors, and our investment in GLE's third-generation enrichment technology that, if successful, we expect will allow us to participate in the entire nuclear fuel value chain.

With extraordinary assets and investments spanning the fuel cycle, a proven operating track record, long-term contract portfolio, strong commitment to sustainability, employee expertise, comprehensive industry knowledge, and a strong balance sheet, the company is pursuing a strategy that it expects will create a platform for strategic growth. We are confident in our ability to increase long-term value by positioning the company as an industry leader at a time when the world's prioritization of energy security, national security and increasing electrification is driving growth in demand, and when geopolitics are creating concerns about the origin and security of supplies across the fuel cycle.

Business segments

URANIUM

Our uranium production capacity is among the world's largest. In 2025, our tier-one production accounted for 15% of world production. We have controlling ownership of the world's largest high-grade mineral reserves.

Product

We have two main subsidiaries:

400

Number of reactors

300

200

100

0

2020 2021 2022 2023 2024 2025

Source: IAEA

Supply uncertainty

Geopolitical uncertainty, energy security, and national security remained the most notable factors impacting security of supply in 2025. Driven by the Russian invasion of Ukraine in 2022, the mine suspension in Niger in 2024, and supply chain challenges, particularly in Kazakhstan, many governments and utilities are re-examining procurement strategies that rely on nuclear fuel supplies from higher risk jurisdictions. In addition, sanctions on Russia and import/export restrictions added to the delivery risks for nuclear fuel supplies coming out of Central Asia. Several idled uranium mines restarted operations in 2025 in support of increased demand, though delays and higher-than-expected production costs were a common theme. Despite the positive price trend in 2025, the deepening geopolitical uncertainty, sanctions and trade policy restrictions, and years of underinvestment in new uranium and fuel cycle service capacities, risk has shifted from producers to utilities.

Supply and trade policy highlights (2025 unless otherwise noted)

Uranium from US inventories

Historically, the DOE was one of the primary sources of secondary supplies in the uranium market. This role has been significantly reduced since the suspension of the barter program of its natural UF6 inventory. The DOE's current primary contribution to secondary supplies is HEU downblending. The vast majority of the DOE's inventory is large volumes of depleted uranium (DU).

In 2018, the DOE announced it was suspending its practice of bartering its excess uranium through the end of 2019. This barter suspension has since been extended on an annual basis. The DOE has indicated a commitment to continue the suspension of the UF6 barter program. There is currently no available timetable to dispose of the remaining natural UF6 in the DOE's excess inventory, estimated at less than 9 million pounds.

The DOE's DU inventory may become available to the market over the next two decades, although a significant portion of the inventory requires either further processing or the development of commercial arrangements before it can be brought to market.

Trade restraints and policies

The importation of Russian uranium into the US market is regulated by the amended USEC Privatization Act and by the Agreement Suspending the Antidumping Action against Russian Uranium Products (RSA), which together impose annual quotas on imports of Russian uranium. These quotas were set at the equivalent of 20% of annual US reactor demand and expired at the end of 2020. An amendment to the RSA was signed that extends the agreement from January 1, 2021, through December 31, 2040, and provides a clear set of rules around access to the US nuclear energy sector by Russian nuclear fuel suppliers. Since 1992, the importation of Russian uranium products in the US has been subject to a quota under the RSA. The amendment reduces the average overall quota and introduces caps, which will reduce the amount of Russian uranium, conversion and enrichment supplied to the US over the long-term. The amendment also includes important new provisions to ensure that all Russian origin uranium must be counted against the quota even if it is imported after further processing in other countries.

The US restrictions do not affect the sale of Russian uranium to other countries. A significant portion of world uranium demand is from utilities in countries that are not affected by the US restrictions. Utilities in some countries, however, adopt policies that limit the amount of Russian uranium they will buy. The Euratom Supply Agency in Europe must approve all uranium related contracts for members of the European Union (EU) and limits the use of certain nuclear fuel supplies from any one source to maintain security of supply, although these limits do not apply to uranium sold separately from enriched uranium product.

Since the Russian invasion of Ukraine on February 24, 2022, many jurisdictions have imposed strict economic sanctions against Russia, including Canada, the US, the EU, the UK, and others. The Canadian government cancelled existing export permits to Russia and ceased issuing new permits for controlled exports to Russia, subject to limited exceptions. The US Government enacted the Prohibiting Russian Uranium Imports Act on May 13, 2024, which banned imports of uranium from Russia as of August 11, 2024, unless the Secretary of Energy grants a waiver to allow such imports. These waivers expire on January 1, 2028, and no new Russian imports would be permitted thereafter. Future related actions by the US administration remain uncertain; however, trade sanctions and Russian export restraints of low-enriched uranium (LEU) to the US will further impact the flow of nuclear fuel supplies coming in and out of Russia, including supplies shipped through Russian ports. The global nuclear industry currently relies on Russia for approximately 14% of its supply of uranium concentrates, 21% of conversion supply, and 42% of enrichment capacity.

In January 2026, the DOE announced US$2.7 billion in task-order awards to strengthen domestic uranium enrichment services and reduce reliance on Russian material, with American Centrifuge Operating, LLC (a subsidiary of Centrus Energy Corp.) and General Matter, Inc. awarded funding to develop high-assay low-enriched uranium (HALEU) enrichment capacity, and Orano Federal Services, LLC (a subsidiary of Orano S.A.) awarded funding to expand LEU enrichment capacity, each with awards of up to US$900 million. The DOE also awarded US$28 million to GLE to advance next generation SILEX laser-based enrichment technology.

Beginning in 2024, actions by the current US administration increased geopolitical and trade uncertainty, as evolving Canada-US tariff measures and related retaliatory actions created volatility and reduced visibility across the bilateral trade environment and nuclear fuel supply chains.

In April 2025, the White House issued an executive order titled "Ensuring National Security and Economic Resilience through Section 232 Actions on Processed Critical Minerals and Derivative Products," directing the Administration to assess and address national security risks arising from US reliance on foreign sources of processed critical minerals, explicitly including uranium. This was followed in January 2026 by a Section 232 presidential proclamation instructing the US Government to begin negotiations with partner countries to secure reliable supply chains for processed critical minerals, including uranium, while reserving authority to impose tariffs or minimum import price floors if negotiations fail. Separately, in April, the US President issued a reciprocal tariff executive order imposing new tariffs on a broad range of imports; however, natural uranium, UF6, and enriched uranium were exempt due to their compliance with the Canada-United States-Mexico Agreement (CUSMA), and a subsequent September executive order further excluded uranium and other critical minerals from country-based global tariffs, preserving the uninterrupted flow of nuclear fuel imports into the US market. The CUSMA is scheduled for its first mandatory joint review in mid-2026.

As ongoing tariff actions between Canada and the US continue to evolve, uncertainty remains on whether additional tariffs or other restrictive trade measures or countermeasures will be implemented and, if so, their scope, magnitude, duration, and applicability to uranium or conversion sales. Such measures could include, among others, increased tariffs on Canadian energy exports, export restrictions on certain commodities (including Canadian energy products), limitations on cross-border supply chains, or the introduction of additional regulatory barriers to trade.

Conversion services

We have about 18% of world UF6 primary conversion capacity and supply UO2 for Canadian-made CANDU reactors. For conversion services, we compete with a small number of primary commercial suppliers to meet global demand. In addition, at times we compete with secondary supplies that come to market as UF6 and are described above.

Changes to contracts

A description of the aspects of our business that we reasonably expect to be affected in the current financial year by renegotiation or termination of contracts or sub-contracts, and the likely effect, is included in Operations, projects and investments beginning on page 29 and Risks that can affect our business beginning on page 114.

Environmental Protection

A description of the financial and operational effects of environmental protection requirements on our capital expenditures, profit or loss and competitive position of Cameco in the current financial year and the expected effect in future years is contained in Decommissioning and financial assurances on pages 39 and 52 in respect of McArthur River, Key Lake and Cigar Lake, Decommissioning on page 69 in respect of Inkai, Estimating decommissioning and environmental remediation costs on page 93 in respect of Westinghouse, Nuclear waste management and decommissioning on page 112 relating to Cameco generally, and Risks that can affect our business on page 114.

‌Operations, projects and investments

Uranium

Tier-one operations

McArthur River mine/Key Lake mill 30

Cigar Lake 44

Inkai 58

Tier-two operations

Rabbit Lake 80

US ISR Operations 80

Advanced projects

Millennium 81

Yeelirrie 82

Kintyre 82

Exploration 83

Fuel services

Refining, conversion and fuel manufacturing

Blind River Refinery 86

Port Hope Conversion Services 86

Cameco Fuel Manufacturing Inc. 87

Westinghouse

Core business 90

New build 91

Other nuclear fuel cycle investments

GLE 94

Uranium production

1 In 2024, record production was achieved due to improved performance of the Key Lake mill. Total packaged production from McArthur River and Key Lake in 2025 was 15.1 million pounds (10.5 million pounds our share), exceeding the revised outlook disclosed on August 28, 2025. Planned production was not achieved due to a shortfall in mine production at McArthur River. The McArthur River mine was unable to fully mitigate the impacts of the delayed development and ground freezing in new mining zones. The mine's performance was also impacted by availability of equipment and certain workforce skills.

2 In 2024, production did not meet expectations due to challenges at Orano's McClean Lake mill caused by ore quality variances and unplanned maintenance issues. Total packaged production from Cigar Lake in 2025 was 19.1 million pounds U3O8 (10.4 million pounds our share) compared to

16.9 million pounds U3O8 (9.2 million pounds our share) in 2024. The operation exceeded our forecast of 18 million pounds (100% basis) as a result of higher productivity and our ability to temporarily adjust annual mine production to make up for past annual production shortfalls, as permitted under our CNSC licence and provincial approval.

3 The Rabbit Lake operation remains in a state of care and maintenance, and we are no longer developing new wellfields at US ISR operations.

Due to equity accounting, our share of production from Inkai is shown as a purchase. JV Inkai's 2026 planned production target is 10.4 million pounds U3O8 (100% basis). See Uranium - Tier-one operations- Inkai beginning on page 58 for more information.

‌Uranium - Tier-one operations

McArthur River mine / Key Lake mill

2025 Production (our share)

2026 Production Outlook (our share)

Estimated Reserves (our share)

Estimated Mine Life

McArthur River is the world's largest, high-grade uranium mine, and Key Lake is the world's largest uranium mill. We are the operator of both the mine and the mill.

McArthur River is considered a material uranium property for us. There is a technical report dated March 29, 2019 (effective December 31, 2018) that can be downloaded from SEDAR+ (https://www.sedarplus.ca) or from EDGAR (https://www.sec.gov).

All values shown, including reserves and resources, represent our share only, unless indicated.

1Production ranges, our share, have been rounded to the nearest half-million.

Business structure

McArthur River is owned by a joint venture (MRJV) between two companies:

Key Lake is owned by a joint venture between the same two companies:

• Cameco - 69.805% (operator) • Cameco - 83.333% (operator)

• Orano - 30.195% • Orano - 16.667%

  History

  1976 • Canadian Kelvin Resources Ltd. and Asamera Oil Corporation Ltd. form an exploration joint venture, which includes the lands that the McArthur River mine is situated on

  1977 • SMDC, one of our predecessor companies, acquires a 50% interest

  1980 • McArthur River joint venture is formed

  • SMDC becomes the operator

  • Active surface exploration begins

  • Between 1980 and 1988, SMDC reduces its interest to 43.991%

    1988 • Eldorado Resources Limited merges with SMDC to form Cameco

  • We become the operator

  • Deposit discovered by surface drilling

    1988-1992 • Surface drilling reveals significant mineralization of potentially economic uranium grades, in a 1,700 metre zone at depths of between 500 to 640 metres

    1992 • We increase our interest to 53.991%

    1993 • Underground exploration program receives government approval - program consists of shaft sinking (completed in 1994) and underground development and drilling

    1995 • We increase our interest to 55.844%

    1997-1998 • Federal authorities issue construction licences for McArthur River after reviewing the environmental impact statement, holding public hearings, and receiving approvals from the governments of Canada and Saskatchewan

    1998 • We acquire all of the shares of Uranerz Exploration and Mining Ltd. (UEM), increasing our interest to 83.766%

  • We sell half of the shares of UEM to Orano, reducing our interest to 69.805%, and increasing Orano's to 30.195%

    1999 • Federal authorities issue the operating licence and provincial authorities give operating approval, and mining begins in December

    2003 • Production is temporarily suspended in April because of a water inflow

  • Mining resumes in July

    2009 • UEM distributes equally to its shareholders:

    − its 27.922% interest in the McArthur River joint venture, giving us a 69.805% direct interest, and Orano a 30.195% direct interest

    − its 33.333% interest in the Key Lake joint venture, giving us an 83.33% direct interest, and Orano a 16.667% direct interest

    2013
    2014	employees at McArthur River and Key Lake operations. World record annual mine production set at McArthur River.
    2017
    2018
    2022
    2023

    • Federal authorities grant a 10-year renewal of the McArthur River and Key Lake operating licences

    • After a two-week labour disruption, we enter into a four-year collective agreement with unionized

    • We announce our plan to temporarily suspend production at McArthur River and Key Lake in 2018

    • We announce the suspension of production at McArthur River and Key Lake for an indeterminate duration

    • We announce plans to transition McArthur River and Key Lake from care and maintenance to planned production of 15 million pounds per year (100% basis) by 2024

    • We updated our production plans for McArthur River and Key Lake to achieve production of 18 million pounds per year (100% basis) starting in 2024

  • In October 2023, the Canadian Nuclear Safety Commission (CNSC) granted 20-year renewals to the licences for both McArthur River and Key Lake

    2024 • World record for annual packaged production set at Key Lake due to improvements and optimization of the Key Lake mill and the availability of sufficient ore feed supplemented by broken ore inventory. Production from the mine was impacted by availability of mobile equipment, certain workforce skills and an unplanned shutdown to accommodate ventilation repairs in shaft 2

    2025 • Planned packaged production at Key Lake was not achieved due to a shortfall in mine production at McArthur River due to delayed development and ground freezing in new mine areas. The mine's performance was also impacted by availability of equipment and certain workforce skills

    Technical report

    For information about uranium sales see pages 22 to 25, environmental matters see Our sustainability principles and practices and The regulatory environment starting on pages 101 and 104, and taxes see page 109.

    For a description of royalties payable to the province of Saskatchewan on the sale of uranium extracted from orebodies within the province, see page 111.

    For a description of risks that might affect access, title or the right or ability to perform work on the property, see Regulatory and governance risks starting at page 126.

This description is based on the project's technical report: McArthur River Operation, Northern Saskatchewan, Canada, dated March 29, 2019 (effective December 31, 2018). The report was prepared for us in accordance with

Canadian National Instrument 43-101 - Standards of Disclosure for Mineral

Projects (NI 43-101), by or under the supervision of Linda Bray, P. Eng., Gregory M. Murdock, P. Eng., and Alain D. Renaud, P. Geo. The following description has been prepared under the supervision of Biman Bharadwaj,

P. Eng., Daley McIntyre, P. Eng., Gregory M. Murdock, P. Eng., and

Alain D. Renaud, P. Geo. They are all qualified persons within the meaning of NI 43-101 but are not independent of us.

The conclusions, projections and estimates included in this description are subject to the qualifications, assumptions and exclusions set out in the technical report. We recommend you read the technical report in its entirety to fully

understand the project. You can download a copy from SEDAR+ (https://www.sedarplus.ca) or from EDGAR (https://www.sec.gov).

About the McArthur River property

Location

The McArthur River mine site is located near Toby Lake, approximately 620 kilometres north of Saskatoon. The mine site is in close proximity to other uranium production operations: the Key Lake mill is 80 kilometres southwest by road and the Cigar Lake mine is 46 kilometres northeast by air.

Access

Access to the property is by an all-weather gravel road and by air. Supplies are transported by truck from Saskatoon and elsewhere. There is a 1.6-kilometre unpaved airstrip and an air terminal one kilometre east of the mine site, on the surface lease.

Saskatoon, a major population centre south of the McArthur River property, has highway, rail and air links to the rest of North America.

Leases

Surface lease

The MRJV acquired the right to use and occupy the lands necessary to mine the deposit under a surface lease agreement with the province of Saskatchewan. The lease covers 1,425 hectares and expires in May 2043.

We are required to report annually on the status of the environment, land development and progress on northern employment and business development.

Mineral lease

We have the right to mine the deposit under ML 5516, granted to us by the province of Saskatchewan. The lease covers 1,380 hectares and expires in March 2034. We have the right to renew the lease for further 10-year terms.

Mineral claims

A mineral claim gives us the right to explore for minerals and to apply for a mineral lease. There are 28 mineral claims, totaling 86,367 hectares, adjoining the mineral lease and surrounding the deposit. The mineral claims are in good standing until 2028, or later.

Environment, social and community factors

The climate is typical of the continental sub-arctic region of northern Saskatchewan. Summers are short and cool even though daily temperatures can sometimes reach above 30°C. The mean daily temperature for the coldest month is below -20°C, and winter daily temperatures can reach below -40°C.

The deposit is 40 kilometres inside the eastern margin of the Athabasca Basin in northern Saskatchewan. The topography and environment are typical of the taiga forested lands in the Athabasca Basin.

We are committed to building long-lasting and trusting relationships with the communities in which we operate. For more information, see Our Sustainability principles and practices at page 101.

No communities are in the immediate vicinity of McArthur River. The community of Wollaston Lake is approximately 120 kilometres by air to the east of the mine site. The community of Pinehouse is approximately 300 kilometres south of the mine by road.

Athabasca Basin community resident employees and contractors fly to the mine site from designated pick-up points. Other employees and contractors fly to the mine from Saskatoon with pick-up points in Prince Albert and La Ronge.

Geological setting

The deposit is in the southeastern portion of the Athabasca Basin in northern Saskatchewan, within the southwest part of the Churchill structural province of the Canadian Shield. The deposit is located at or near the unconformity contact between the Athabasca Group sandstones and underlying metasedimentary rocks of the Wollaston Domain.

The deposit is similar to other Athabasca Basin deposits but is distinguished by its very high grade and overall size. Unlike Cigar Lake, there is no development of extensive hydrothermal clay alteration in the sandstone above the uranium mineralization and the deposit is relatively simple geochemically with negligible amounts of other metals.

McArthur River's geological setting is similar to the Cigar Lake deposit in that the sandstone that overlies the deposit and basement rocks contains large volumes of water at significant pressure.

Mineralization

McArthur River's mineralization is structurally controlled by a northeast-southwest trending reverse fault (the P2 fault), which dips 40-65 degrees to the southeast and has thrust a wedge of basement rock into the overlying sandstone with a vertical displacement ranging between 60 and 80 metres.

The deposit consists of nine mineralized areas with delineated mineral resources and/or reserves: Zones 1, 2, 3, 4, 4 South, A, B, McA North 1 and McA North 2. These and three under-explored mineralized showings, known as McA North 3, McA North 4 and McA South 1, as well as other mineralized occurrences have been identified over a strike length of approximately

2,700 metres.

The main part of the mineralization, generally at the upper part of the basement wedge, averages 12.7 metres in width and has a vertical extent ranging between 50 metres and 120 metres.

The deposit has two distinct styles of mineralization:

• high-grade mineralization at the unconformity near the P2 reverse fault and within both sandstone and basement rocks; and

• fracture controlled and vein like mineralization that occurs in the sandstone away from the unconformity and within the basement quartzite.

  The high-grade mineralization along the unconformity constitutes most of the mineralization within the McArthur River deposit. Mineralization occurs across a zone of strongly altered basement rocks and sandstone across both the unconformity and the P2 structure. Mineralization is generally within 15 metres of the basement/sandstone contact with the exception of Zone 2.

  Uranium oxide in the form of uraninite and pitchblende (+/- coffinite) occurs as disseminated grains in aggregates ranging in size from millimetres to decimetres, and as massive mineralization up to several metres thick.

  Geochemically, the deposit does not contain any significant quantities of the elements nickel, copper, cobalt, lead, zinc, molybdenum, and arsenic that are present in other unconformity related Athabasca uranium deposits although locally elevated quantities of these elements have been observed in Zone B.

  Deposit type

  McArthur River is an unconformity-associated uranium deposit. Deposits of this type are believed to have formed through an oxidation-reduction reaction at a contact where oxygenated fluids met with reducing fluids. The geological model was confirmed by surface drilling, underground drilling, development, and production activities.

  About the McArthur River operation

  McArthur River is a fully developed property with sufficient surface rights to meet current mining operation needs. We began construction and development of the McArthur River mine in 1997 and completed it on schedule. Mining began in December 1999 and commercial production on November 1, 2000.

  In February 2018, we began a planned 10-month production suspension. In response to market conditions, in July 2018, we extended the suspension for an indefinite duration. In February 2022, we announced and began the transition from care and maintenance back into production.

  We have successfully packaged approximately 373.2 million pounds (100% basis) since we began mining in 1999.

  The mineral reserves at McArthur River are contained within seven zones: Zones 1, 2, 3, 4, 4 South, A and B. There are currently two active mining zones (Zone 2 and 4), one with development significantly advanced (Zone 1), and one in the mid stages of development (Zone 4 South).

  Zone 2 has been actively mined since production began in 1999. The ore zone was initially divided into three freeze panels. As the freeze wall was expanded, the inner connecting freeze walls were decommissioned to recover the inaccessible uranium around the active freeze pipes. Mining of Zone 2 is almost complete. About 3.5 million pounds of mineral reserves remain secured behind a freeze wall, and we expect to recover them using a combination of raisebore and blasthole stope mining.

  Zone 4 has been actively mined since 2010. The zone was divided into four freeze panels, and like in Zone 2, as the freeze wall was expanded, the inner connecting freeze walls were decommissioned. Zone 4 has 73.0 million pounds of mineral reserves secured behind freeze walls, and it will be the main source of production for the next several years. Raisebore and blasthole stope mining will be used to recover the mineral reserves.

  Zone 1 is the next planned mine area to be brought into production. Freeze hole drilling was completed in 2023 and brine distribution construction and commissioning was completed in 2024. Freeze wall formation around the zone was successfully achieved in November 2025, securing 48.1 million pounds of reserves behind frozen ground. Development and construction of the drill and extraction chambers inside the freeze wall is currently in progress. We expect production mining from this area to begin in 2026. Blasthole stope mining is planned as the main extraction method in Zone 1.

  Zone 4 South development began in 2015 and is in the mid development stage. Freeze drilling, brine distribution and freeze wall activation on the upper levels is near completion and is expected to be complete in 2026. Development of the lower freeze drifts remains in progress and is also expected to be completed in 2026. Freeze drilling on the lower levels is expected to begin mid-2026. Freeze plant and heat exchanger expansion is in progress to support the mining of this zone.

  Continued underground exploration activities are planned in 2026.

  Permits

  We need three key permits to operate the McArthur River mine:

• Uranium Mine Operating Licence - renewed in 2023 and expires in October 2043 (from the CNSC);

• Approval to Operate Pollutant Control Facilities - renewed in 2022 and expires on June 30, 2028 (from the Saskatchewan Ministry of Environment (SMOE)); and

• Water Rights Licence and Approval to Operate Works - amended in 2011 and valid for an undefined term (from the Saskatchewan Watershed Authority).

  The CNSC licence conditions handbook allows McArthur River to produce up to 25.0 million pounds (100% basis) per year.

  Infrastructure

  Surface facilities are 550 metres above sea level. The site includes:

• an underground mine with three shafts: one full service shaft and two ventilation shafts

• 1.6-kilometre gravel airstrip and air terminal

• waste rock stockpiles

• water containment ponds and treatment plant

• a freshwater pump house

• a powerhouse

• electrical substations

• backup electrical generators

• a warehouse

• freeze plants

• a concrete batch plant

• an administration and maintenance shop building

• a permanent residence and recreation facilities

• an ore slurry load out facility

  Water, power and heat

  Toby Lake, which is nearby and easy to access, has enough water to satisfy all surface water requirements. Collection of groundwater that naturally enters our shafts is sufficient to meet all underground process water requirements and supplements the surface industrial water supply. The site is connected to the provincial power grid, and it has backup generators in case there is an interruption in grid power.

  McArthur River operates throughout the year despite cold winter conditions. During the winter, we heat the fresh air necessary to ventilate the underground workings using propane-fired burners.

  Employees

  Employees are recruited with preference given to residents of northern Saskatchewan.

  The collective agreement with United Steelworkers Local 8914 ended on December 31, 2025. Negotiations for a new agreement have commenced. As in past negotiations, work continues under the terms of the expired agreement.

  Mining

  The McArthur River deposit presents unique challenges that are not typical of traditional hard or soft rock mines. These challenges are the result of mining in or near high pressure ground water in challenging ground conditions with significant radiation concerns due to the high-grade uranium ore. We take significant steps and precautions to reduce the risks. Mine designs and mining methods are selected based on their ability to mitigate hydrological, radiological, and geotechnical risks. Operational experience gained since the start of production has resulted in a significant reduction in risk. However, there is no guarantee that our efforts to mitigate risk will be successful.

  Mining methods and techniques

  All the mineralized areas discovered to date at McArthur River are in, or partially in, water-bearing ground with significant pressure at mining depths.

  There are three approved mining methods at McArthur River: raisebore mining, blasthole stope mining and boxhole mining. However, only raisebore and blasthole stope mining remain in use. Before we begin mining an area, we freeze the ground around it by circulating chilled brine through freeze holes to form an impermeable frozen barrier.

  Blasthole stope mining

  Blasthole stope mining began in 2011 and is the main extraction method planned for future production. It is planned in areas where blastholes can be accurately drilled and small stable stopes excavated without jeopardizing the freeze wall integrity. The use of this method has allowed the site to improve operating costs by increasing overall extraction efficiency by reducing underground development, concrete consumption, mineralized waste generation and improving extraction cycle time.

  Raisebore mining

  Raisebore mining is an innovative non-entry approach that we adapted to meet the unique challenges at McArthur River, and it has been used since mining began in 1999. This method is favourable for mining the weaker rock mass areas of the deposit and is suitable for massive high-grade zones where there is access both above and below the ore zone.

  Initial processing

  McArthur River produces two product streams, high grade slurry and low-grade mineralized rock. Both product streams are shipped to the Key Lake mill to produce uranium ore concentrate.

  The high-grade material is ground and thickened into a slurry underground and then pumped to surface. The material is then thickened and blended for grade control and shipped to Key Lake in slurry totes using haul trucks.

  The low-grade mineralized material is hoisted to surface and shipped as a dry product to Key Lake using covered haul trucks. Once at Key Lake, the material is ground, thickened and blended with the high-grade slurry to a nominal 5% U3O8 mill feed grade. It is then processed into uranium ore concentrate and packaged in drums for further processing offsite.

  Tailings

  McArthur River does not have a tailings management facility (TMF) as it ships all mineralized material to Key Lake for milling and processing.

  Waste rock

  The waste rock piles are confined to a small footprint on the surface lease and managed in contained facilities. These are separated into three categories:

• clean waste (includes mine development waste, crushed waste, and various piles for concrete aggregate and backfill);

• low-grade mineralized material that is temporarily stored on lined pads until trucked to Key Lake; and

• waste with acid-generating potential - temporarily stored on lined pads - for concrete aggregate.

  Water inflow incidents

  There have been two notable water inflow incidents at the McArthur River mine. These two inflows have strongly influenced our mine design, inflow risk mitigation and inflow preparedness:

  Bay 12 Inflow: Production was suspended on April 6, 2003, as increased water inflow due to a rock fall in a new development area (Bay 12 located just above the 530-metre level) began to flood the lower portions of the mine, including the underground grinding circuit area. Additional dewatering capacity was installed, and the flooded areas were dewatered and repaired. We resumed mining in July 2003 and sealed off the excess water inflow in July 2004.

  590-7820N Inflow: In November 2008, there was a small water inflow in the lower Zone 4 development area on the 590-metre level. It did not impact production but did delay local development for approximately one year. In January 2010, the inflow was sealed off and local development was resumed.

  Pumping capacity and treatment limits

  Our standard for this mine is to secure pumping capacity of at least one and a half times the estimated maximum sustained inflow. We review our dewatering system and requirements at least once a year and before we begin work on any new zone. As our mine plan is advanced, our dewatering system will be expanded to handle water from the new mine areas. We believe we have sufficient pumping, water treatment and surface storage capacity to handle the estimated maximum sustained inflow.

  Production

  The production plan is designed to process all current McArthur River mineral reserves plus low-grade mineralized waste from development and Key Lake low-grade stockpiled mineralization remaining from the Deilmann and Gaertner pits. In addition, a small amount of recycled product from Blind River and Port Hope facilities is planned to be processed. The following is a general summary of the production plan over the expected life of asset on a 100% basis for these mineral reserves, mineralized material, and product:

  Target annual production • 18 million pounds U3O8

  Average mine production • 200 to 400 tonnes of ore per day, varying with grade

  Total mill feed • 3,265,000 tonnes of mineralized feed (including 2,627,000 tonnes of McArthur

  material)

  Average mill feed grade • 4.85% U3O8

  Total mill production • 346.6 million pounds of U3O8 packaged based on total planned mill feed and an

  average recovery of 99.2%

  Production Update

  Packaged production in 2025 was impacted by a shortfall in mine production at McArthur River. The McArthur River mine was unable to fully mitigate the impacts of the delayed development and ground freezing in new mining areas. The mine's performance was also impacted by availability of equipment and certain workforce skills. This resulted in constrained mill feed and a six-week unplanned mill shutdown in the fall of 2025, which limited the mill's ability to consistently operate at planned rates and ultimately impacted the achievement of initial production targets.

  The Key Lake mill saw notable improvements in its operational performance in 2025, with the site becoming more familiar and experienced with new equipment and control system upgrades. In addition, the systematic understanding of process bottlenecks and efforts to remove or decrease their impacts allowed Key Lake to optimize the mill throughput rates.

  We plan to produce from 14 million to 16.5 million pounds (100% basis) in 2026 (our share is approximately 10.0 million to 11.5 million pounds). The production rate is currently constrained by limited ore feed supply as a result of delays in new mining areas at McArthur River. In 2026, we expect to bring zone 1 into production, which will notably improve the number of mining fronts available. In addition, we will continue to advance zone 4 south development while adding to our workforce and replacing mobile equipment. We also plan to continue with our underground exploration activities in 2026. There are several operational risks that could impact the 2026 production plan, including the transition to new mine areas, the availability of personnel with the necessary skills and experience, aging infrastructure, and the potential impact of supply chain challenges on the availability of materials, reagents and equipment that carry with them the risks of not achieving our production plans. In addition, there is a risk of a delayed restart or reduced productivity at Key Lake mill following its annual maintenance shutdown, as the planned installation and commissioning of new infrastructure and repairs to major existing infrastructure during the outage could lead to integration or ramp-up challenges that impact planned production levels.

  Licensed annual production capacity

  The McArthur River mine and Key Lake mill are both licensed to produce up to 25 million pounds (100% basis) per year. To achieve annual production at the licensed capacity, additional investment will be required.

  We are addressing aging infrastructure and potential bottlenecks at Key Lake and the advancement of freezing at McArthur River to ensure reliability and sustainability. While these projects are required to support and maintain capacity at current production levels, they have been classified as growth because they also position us for future production flexibility, including to its licensed annual capacity of 25 million pounds, although no decision on future production levels has been made. We will plan our production in line with market opportunities and our contract portfolio, demonstrating that we continue to be a responsible, long-term supplier of uranium fuel.

  Key Lake mill

  Location and access

  The Key Lake mill is located in northern Saskatchewan, 570 kilometres north of Saskatoon. The site is 9 kilometres long and 5 kilometres wide and is connected to McArthur River by an 80-kilometre all-weather road. There is a 1.6-kilometre unpaved airstrip and an air terminal on the east edge of the site.

  Permits

  We need two key permits to operate the Key Lake mill:

• Uranium Mill Operating Licence - renewed in October 2023 and expires in October 2043 (from the CNSC); and

• Approval to Operate Pollutant Control Facilities - renewed in 2021 and expires on November 30, 2029 (from the SMOE) The CNSC licence conditions handbook allows the Key Lake mill to produce up to 25.0 million pounds (100% basis) per year. Supply

  All McArthur River ore, including our share, is milled at Key Lake. We do not have a formal toll milling agreement with the Key Lake joint venture.

  In June 1999, the Key Lake joint venture (Cameco and UEM) entered a toll milling agreement with Orano to process their total share of McArthur River ore. The terms of the agreement (as amended in January 2001) include the following:

• processing is at cost, plus a toll milling fee; and

• the Key Lake joint venture owners are responsible for decommissioning the Key Lake mill and for certain capital costs, including the cost of any tailings management associated with milling Orano's share of McArthur River ore.

  With the UEM distribution in 2009 (see History on page 31 for more information), we made the following changes to the agreement:

• The fees and expenses related to Orano's pro-rata share of ore produced just before the UEM distribution (16.234% - the first ore stream) have not changed. Orano is not responsible for any capital or decommissioning costs related to the first ore stream.

• The fees and expenses related to Orano's pro-rata share of ore produced as a result of the UEM distribution (an additional 13.961% - the second ore stream) have not changed. Orano's responsibility for capital and decommissioning costs related to the second ore stream are, however, as a Key Lake joint venture owner under the original agreement.

  The agreement was amended again in 2011 and now requires:

• milling of the first ore stream at the Key Lake mill until May 31, 2028; and

• milling of the second ore stream at the Key Lake mill for the entire life of the McArthur River project.

  Processing

  McArthur River low-grade mineralization, including legacy low-grade mineralized waste rock stored at Key Lake, is ground and thickened at Key Lake and then blended with McArthur River high-grade slurry to a nominal 5% U3O8 mill feed grade. All remaining uranium processing (leaching through to calcined uranium ore concentrate packaging) and tailings disposal also occur at Key Lake.

  The Key Lake mill comprises the following eight plants:

• ore slurry receiving plant;

• grinding/blending plant;

• reverse osmosis plant;

• leaching/counter current decantation plant;

• solvent extraction plant;

• yellowcake precipitation/calcining/packaging/ammonium sulfate plant;

• bulk neutralization/lime handling/tailings treatment and pumping; and

• powerhouse/utilities/acid plant/oxygen plant complex.

  Recovery and metallurgical testing

  The McArthur River original flowsheet was largely based on the use of conventional mineral processing concepts and equipment. Where necessary, testwork was undertaken to prove design concepts or adapt conventional equipment for unique services. Simulated ore was utilized in much of the testwork because the off-site testing facilities were not licensed to receive radioactive materials. Testwork at the Key Lake metallurgical laboratory also confirmed the suitability of the Key Lake mill circuit for processing McArthur River ore with some Key Lake circuit modifications.

  To date, numerous changes have been made to both the McArthur River and Key Lake processing and water treatment circuits to improve their operational reliability and efficiency. From a uranium recovery perspective, the most important was to change the McArthur River grinding circuit classification system from screens to cyclones. This was completed in late 2009 and provided a measurable recovery increase as well as reduced particle segregation issues. Based on average operating results achieved during the periods from 2009 to 2017, inclusive, and from 2023 to 2025, inclusive, the Key Lake mill recorded an average annual recovery of approximately 99.2%, which is assumed to be maintained. Testing at Key Lake has shown that use of a silica coagulant was able to alleviate the issues caused by the cement dilution in the ore from McArthur River. This has eliminated the need to operate the gravity concentrator circuit as well as increased the solvent extraction circuit operational reliability.

  Waste rock

  There are five rock stockpiles at the Key Lake site:

• Three contain non-mineralized waste rock. These will be decommissioned when the site is closed.

• Two contain low-grade mineralized material. These are used to reduce the grade of McArthur River ore slurry before it enters the mill circuits to maintain a nominal 5% U3O8 ore feed grade.

  Treatment of effluent

  We modified Key Lake's effluent treatment process to satisfy our licence and permit requirements.

  Tailings capacity

  There are two TMFs at the Key Lake site:

• An above-ground impoundment facility, where tailings are stored within compacted till embankments. We have not deposited tailings here since 1996, and are looking at several options for decommissioning this facility in the future.

• The Deilmann open pit, which was mined out in the 1990s. Tailings from processing McArthur River ore are deposited in the Deilmann in-pit TMF.

Beginning in July 2001, periodic sloughing of the pit walls in the western portion of the Deilmann TMF was experienced. We implemented a long-term stabilization plan, with the final phase completed in 2019.

Based upon the current licence conditions, tailings capacity is sufficient to mill all the known McArthur River mineral reserves and resources, should they be converted to reserves, with additional capacity to toll mill ore from other regional deposits.

Decommissioning and financial assurances

Updated preliminary decommissioning plans for McArthur River and Key Lake were submitted in 2022 as part of the regular five-year update schedule. Prior to revising the letters of credit, approval of the updated plans is required from the province of Saskatchewan and CNSC staff as well as formal approval from the CNSC through a Commission proceeding. The necessary approvals were received for McArthur River in 2025 and updated financial assurances are in place. A formal Commission proceeding will be required for final approval of the updated preliminary decommissioning plans for Key Lake. The existing financial assurance remains in place for Key Lake and will be updated upon regulatory acceptance of the updated documents.

For more information, see Nuclear waste management and decommissioning.

Operating and capital costs

The following is a summary of the operating and capital cost estimates for the life of mine, stated in constant 2025 dollars and reflecting a forecast life-of-mine mill production of 346.6 million pounds U3O8 packaged.

Total operating cost per pound U3O8 $21.72

Note: Presented as total cost to the McArthur River Joint Venture.

Estimated operating costs to the MRJV consist of annual expenditures at McArthur River to mine the mineral reserves, process it underground, including grinding, thickening, and pumping the resulting slurry to surface and transporting it to Key Lake, as well as the costs associated with the low-grade mineralized waste brought to surface and transported to Key Lake for ore blending purposes.

Operating costs at Key Lake consist of costs for receipt of the slurry, grinding of mineralized waste for blending, processing of the ore up to and including precipitation, dewatering, calcining and packaging of the yellowcake into drums, including the cost of tailings placement for long-term storage in the Deilmann TMF.

We expect increased operating costs primarily related to maintaining the long-term reliability of our assets at both sites. Maintenance costs have increased substantially in the past year due to increases in the costs of materials and supplemental contractor labour.

Notes:

1. Presented as total cost to the MRJV.

2. Mine development includes delineation drilling, mine development, probe and grout drilling, freeze drilling, and minor support infrastructure.

Estimated capital costs to the MRJV include sustaining costs for both McArthur River and Key Lake, as well as underground development at McArthur River to bring undeveloped mineral reserves into production. Overall, the largest segment of capital at McArthur River is mine development. Other significant capital includes freeze infrastructure costs.

Capital costs at Key Lake have increased due to inflationary pressures on project execution as well as investments to address aging infrastructure to help ensure the long-term sustainability of the operation.

The economic analysis, effective as of December 31, 2018, being the effective date of the technical report for McArthur River and Key Lake operations, resulted in an estimated pre-tax net present value (NPV) (at a discount rate of 8%) to Cameco for net cash flows from January 1, 2019 forward of $2.97 billion for its share of the current McArthur River mineral reserves. Using the total capital invested to December 31, 2018, along with the operating and capital estimates for the remainder of the mineral reserves, the pre-tax internal rate of return (IRR) was estimated to be 11.6%.

The analysis was from the point of view of Cameco, which owns 69.805% of the MRJV, and incorporated a projection of Cameco's sales revenue from its proportionate share of the related production, less its share of related operating and capital costs of the MRJV, as well as royalties and surcharges that will be payable on the sale of concentrates.

For the purpose of the economic analysis, the projected impact of income taxes was excluded due to the nature of the required calculations. McArthur River operates as an unincorporated joint venture and is, therefore, not subject to direct income taxation at the joint venture level. It is not practical to allocate a resulting income tax cost to Cameco's portion of the