Cameco lifts Cigar Lake stake to 57.4%

Cameco Corporation is increasing its ownership stake in the Cigar Lake uranium mine by acquiring part of TEPCO Resources Inc.’s 5% joint-venture interest for approximately $115.75 million, subject to customary closing adjustments and regulatory approvals.

Rhea-AI Filing Summary

Cameco Corporation is increasing its ownership stake in the Cigar Lake uranium mine by acquiring part of TEPCO Resources Inc.’s 5% joint-venture interest for approximately $115.75 million, subject to customary closing adjustments and regulatory approvals. Upon closing, Cameco’s interest will rise by 2.871 percentage points to 57.418%, while Orano Canada Inc.’s stake will increase to 42.582%. Cigar Lake is described as a high-grade, safe and cost-effective uranium operation with proven and probable reserves of 172.4 million pounds of U3O8 and additional measured, indicated and inferred resources as of December 31, 2025. Since starting production in 2014, it has produced about 174.5 million packaged pounds, and 2026 production is expected between 17.5 million and 18 million pounds on a 100% basis. Cameco plans to maintain production in the current CLMain area and advance CLExt development work to extend mine life to 2036, with capital projects aligned to its disciplined contracting, operational and capital allocation strategy.

Key Figures

Purchase cost: $115.75 million Cameco post-deal stake: 57.418% Orano post-deal stake: 42.582% +5 more

8 metrics

Purchase cost $115.75 million Cameco’s share of TEPCO’s Cigar Lake interest, subject to adjustments

Cameco post-deal stake 57.418% Ownership in Cigar Lake mine after closing

Orano post-deal stake 42.582% Ownership in Cigar Lake mine after closing

Ownership increase 2.871 percentage points Incremental stake Cameco gains in Cigar Lake

Proven & probable reserves 172.4 million pounds U3O8 Cigar Lake, 100% basis, as of December 31, 2025

Measured & indicated resources 26.3 million pounds U3O8 Cigar Lake, 100% basis, as of December 31, 2025

Inferred resources 20.0 million pounds U3O8 Cigar Lake, 100% basis, as of December 31, 2025

2026 production outlook 17.5–18 million pounds U3O8 Planned Cigar Lake output, 100% basis

Key Terms

proven and probable reserves, measured and indicated resources, inferred resources, NI 43-101, +1 more

5 terms

proven and probable reserves financial

"Cigar Lake’s reserve and resource base includes proven and probable reserves estimated at 172.4 million pounds of U3O8"

Proven and probable reserves are estimates of how much of a natural resource (like oil, gas or a mineral) a company can realistically extract: “proven” means there’s strong evidence it can be recovered, while “probable” means there’s a reasonable but lower level of confidence. Investors care because these estimates shape expected future production, revenue and risk—think of proven reserves as items you can see in your pantry and probable reserves as likely items tucked in bags you expect to find.

measured and indicated resources financial

"measured and indicated resources of approximately 26.3 million pounds, and inferred resources of 20.0 million pounds"

Measured and indicated resources are two levels of confidence in estimates of a mineral deposit’s size and quality: ‘measured’ is the highest-confidence estimate, while ‘indicated’ is a somewhat less certain but still reliable estimate. Think of measured like ingredients weighed on a kitchen scale and indicated like amounts estimated by eye; together they tell investors how much material is likely present and how predictable future extraction and costs may be, which affects project valuation and risk assessment.

inferred resources financial

"measured and indicated resources of approximately 26.3 million pounds, and inferred resources of 20.0 million pounds"

An inferred resource is an early-stage estimate of how much mineral or fuel may be present in the ground based on limited geological evidence and sampling. Think of it like seeing scattered clues that suggest a buried treasure might exist but not having dug enough to be sure; the potential size and value are uncertain. For investors it signals possible upside but carries high risk and should not be treated as proven supply or relied on for firm production plans.

NI 43-101 regulatory

"Qualified Persons The technical and scientific information discussed in this document for Cigar Lake was approved by the following individuals who are qualified persons for the purposes of NI 43-101"

A Canadian regulatory standard that sets the rules for how mining and exploration companies must report mineral resources and reserves, requiring technical reports prepared or signed off by an independent, certified expert. It matters to investors because it creates a consistent, transparent “inspection report” for mining projects, making it easier to compare prospects, judge the reliability of claims, and assess geological and financial risk before investing.

forward-looking information regulatory

"This news release includes statements and information about our expectations for the future, which we refer to as forward-looking information"

Forward-looking information are predictions, plans, estimates or expectations about a company’s future performance, results or events, such as sales forecasts, project timelines, or anticipated costs. It matters to investors because these statements guide expectations but rely on assumptions and uncertain factors—like a weather forecast for a business—so investors should treat them as informed guesses rather than guarantees and consider the risks and possible changes behind the numbers.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What transaction did Cameco (CCJ) announce regarding the Cigar Lake mine?

Cameco agreed with Orano Canada and TEPCO Resources for TEPCO to sell its 5% interest in the Cigar Lake joint venture. After closing, Cameco’s ownership in the Cigar Lake uranium mine will increase by 2.871 percentage points to 57.418%.

How much will Cameco (CCJ) pay to increase its Cigar Lake ownership?

Cameco’s purchase cost for its share of TEPCO’s Cigar Lake interest is approximately $115.75 million, subject to customary closing adjustments. The acquisition remains contingent on certain regulatory approvals and standard closing conditions before it can be completed.

When is Cameco (CCJ) expecting the Cigar Lake stake acquisition to close?

Cameco expects the transaction to close in the third quarter of 2026, assuming required regulatory approvals are obtained and other standard closing conditions are satisfied. The timing could change if approvals or conditions are not met as anticipated.

What are the current reserves and resources at Cigar Lake mentioned by Cameco (CCJ)?

Cigar Lake has proven and probable reserves estimated at 172.4 million pounds of U3O8 on a 100% basis as of December 31, 2025. It also has measured and indicated resources of about 26.3 million pounds and inferred resources of 20.0 million pounds.

What production levels does Cameco (CCJ) forecast for Cigar Lake in 2026?

For 2026, Cameco’s outlook for Cigar Lake calls for production between 17.5 million and 18 million pounds of uranium concentrate (U3O8) on a 100% basis. This follows cumulative production of roughly 174.5 million packaged pounds since 2014.

How long does Cameco (CCJ) plan to operate the Cigar Lake mine?

Cameco plans to continue production and development in the CLMain area while advancing CLExt development work needed to extend Cigar Lake’s mine life to 2036. Planned projects include a freeze pad, freeze distribution systems, and underground infrastructure improvements.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 06/01/2026 - 04:04 PM Learn about SEC filing dates

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13A-16 OR 15D-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of June, 2026

Commission File Number 1-14228

Cameco Corporation

(Translation of Registrant’s Name into English)

2121-11th Street West

Saskatoon, Saskatchewan, Canada S7M 1J3

(Address of Principal Executive Offices)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F          Form 40-F  ✓  

Exhibit Index

Exhibit No.		Description
99.1		Press Release dated June 1, 2026

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: June 1, 2026				Cameco Corporation
				By: /s/ R. Liam Mooney
				R. Liam Mooney
				Senior Vice-President and Chief Legal Officer

Exhibit 99.1

NEWS RELEASE   All amounts in Canadian dollars unless specified otherwise www.cameco.com   Saskatoon   Saskatchewan Canada

Cameco Increases Ownership Stake in Cigar Lake Mine

June 1, 2026

Cameco (TSX: CCO; NYSE: CCJ) and Orano Canada Inc. (Orano) have reached agreement with TEPCO Resources Inc. (TEPCO) to acquire TEPCO’s 5% participating interest in the Cigar Lake Joint Venture. Upon closing, Cameco’s ownership stake in the Cigar Lake uranium mine in northern Saskatchewan will increase by 2.871 percentage points to 57.418%, while Orano’s share will rise by 2.129 percentage points to 42.582%.

“Cigar Lake is among the world’s best uranium mines, producing the highest-grade uranium ore from a safe, reliable, and cost-effective operation,” said Cameco’s Chief Executive Officer Tim Gitzel. “Increasing our ownership in this world-class, tier-one asset further demonstrates our commitment to our strategy, with scarce, licensed, permitted assets like Cigar Lake playing an essential role in fueling global ambitions to expand nuclear energy generation. Cigar Lake’s success wouldn’t be possible without supportive neighbouring Indigenous communities, which provide vital workforce and supply chain support through our mutually beneficial partnerships.”

Cameco’s purchase cost to acquire our respective share of TEPCO’s interest in Cigar Lake is approximately $115.75 million, subject to customary closing adjustments. The acquisition is subject to certain regulatory approvals and other standard closing conditions. The transaction is expected to close in the third quarter of 2026.

Cigar Lake’s reserve and resource base includes proven and probable reserves estimated at 172.4 million pounds of U₃O₈, measured and indicated resources of approximately 26.3 million pounds, and inferred resources of 20.0 million pounds (100% basis, as of December 31, 2025). Since the time it began production in 2014, Cigar Lake has produced approximately 174.5 million packaged pounds (100% basis, as of December 31, 2025).

Our 2026 production outlook for the Cigar Lake mine is between 17.5 million and 18 million pounds of uranium concentrate (U₃O₈) on a 100% basis. In 2026, we plan to continue production and development activities in the area currently being mined (CLMain), while continuing to advance the development work related to Cigar Lake extension (CLExt) that is required to extend the life of the mine to 2036. Planned capital projects related to CLExt include construction of a freeze pad, freeze distribution, and underground infrastructure, with capital investments at Cigar Lake remaining consistent and aligned with our disciplined contracting, operational and capital allocation strategy.

Cigar Lake proven and probable mineral reserves

PROVEN

PROBABLE

TOTAL MINERAL RESERVES

PROPERTY

MINING METHOD

TONNES

GRADE % U3O8

CONTENT (LB U3O8)

TONNES

GRADE % U3O8

CONTENT (LB U3O8)

TONNES

GRADE % U3O8

CONTENT (LB U3O8)

METALLURGICAL RECOVERY (%)

Cigar Lake

UG

263.7

17.06

99.2

215.3

15.43

73.2

479.0

16.33

172.4

98.9

As of December 31, 2025 (100% basis); tonnes in thousands; pounds in millions)

Cigar Lake measured, indicated and inferred mineral resources

MEASURED RESOURCES (M)

INDICATED RESOURCES (I)

TOTAL M+I

INFERRED RESOURCES

GRADE

CONTENT

GRADE

CONTENT

CONTENT

GRADE

CONTENT

PROPERTY

TONNES

% U3O8

(LB U3O8)

TONNES

% U3O8

(LB U3O8)

(LB U3O8)

TONNES

% U3O8

(LB U3O8)

Cigar Lake

82.3

5.00

9.1

153.8

5.07

17.2

26.3

163.4

5.55

20.0

As of December 31, 2025 (100% basis); tonnes in thousands; pounds in millions)

Please see pages 97 and 98 of Cameco’s 2025 annual information form for the key assumptions, parameters and methods used to estimate the Cigar Lake mineral reserves and resources.

Qualified Persons

The technical and scientific information discussed in this document for Cigar Lake was approved by the following individuals who are qualified persons for the purposes of NI 43-101:

● Kirk Lamont, general manager, Cigar Lake, Cameco

● Scott Bishop, director, technical services, Cameco

Caution about Forward-Looking Information

This news release includes statements and information about our expectations for the future, which we refer to as forward-looking information. Forward-looking information is based on our current views, which can change significantly, and actual results and events may be significantly different from what we currently expect. Examples of forward-looking information in this news release include: our views regarding the grade of uranium ore produced from Cigar Lake; our views regarding the safety, reliability and cost-effectiveness of Cigar Lake operations; our views regarding Cigar Lake’s ability to support the global ambitions to increase nuclear energy generation; our expectations regarding closing adjustments to Cameco’s purchase price; whether regulatory approvals will be granted and closing conditions will be met within the expected timeframes; our expectations as to the closing date; the 2026 production outlook for Cigar Lake; the present estimate of proven and probable reserves and measured, indicated and inferred resources remaining at Cigar Lake; the continuation of production and development activities in CLMain; our plan to extend the mine life at Cigar Lake to 2036; our planned capital projects related to CLExt including construction of a freeze pad, freeze distribution, and underground infrastructure; and whether capital investments at Cigar Lake will remain consistent and aligned with our disciplined contracting, operational and capital allocation strategy. Material risks that could lead to different results include: failure to obtain regulatory approvals or meet closing conditions within the expected timeframes; unexpected changes in uranium supply, demand, long-term contracting and prices; the risk that we may not be able to implement our planned production and development activities in CLMain, our development work related to CLExt, or our planned capital projects related to CLExt; the risk that we may not be able to extend the life of mine to 2036; the risk that we may not be able to continue to align production decisions with market opportunities and our contract portfolio; the risk that the contracting, operational and capital allocation strategy we are pursuing may prove unsuccessful, or that we may not be able to execute it successfully; the risk of disruption to operations at Cigar Lake or the McClean Lake mill for technical, regulatory or labour reasons; and the risk of disruptions to power, communication services and road access due to floods or wildfires. In presenting the forward-looking information, we have made material assumptions which may prove incorrect about: timeframes to obtain regulatory approvals and meet closing conditions; uranium supply, demand, long-term contracting and prices; the market conditions and other factors upon which we have based our future plans and forecasts; the success of our plans and strategies, including CLExt and planned capital projects; the absence of new and adverse government regulations, policies or decisions; that there will not be any disruption to operations at Cigar Lake or the McClean Lake mill for technical, regulatory or labour reasons; and that there will not be disruptions to power, communication services and road access due to floods or wildfires. Please also review the discussion in our 2025 annual MD&A and most recent annual information form for other material risks that could cause actual results to differ significantly from our current expectations, and other material assumptions we have made. Forward-looking information is designed to help you understand management’s current views of our near-term 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 securities laws.

Profile

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.

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Investor inquiries				Media inquiries
Cory Kos				Veronica Baker
306-716-6782				306-385-5541
cory_kos@cameco.com				veronica_baker@cameco.com

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