Cameco releases McArthur River technical update

Rhea-AI Filing Summary

Key Terms

Cameco Corporation (CCJ) voluntarily filed a technical report on its McArthur River operation under NI 43-101 to provide updated information.

Available on EDGAR 11/05/2026 - 02:28 PM EST Accepted by SEC EDGAR 11/05/2026 - 02:28 PM EST

Filing Impact

(Moderate)

Filing Sentiment

(Neutral)How Sentiment works

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Form Type

6-K

Cameco Corporation (CCJ) voluntarily filed a technical report on its McArthur River operation under NI 43-101 to provide updated information. The report was not filed as a result of a change in mineral reserves or mineral resources that constitutes a material change in relation to Cameco. It is available on Cameco’s website, SEDAR+ and EDGAR.

Date: November 5, 2026

Cameco Corporation

/s/ R. Liam Mooney

R. Liam Mooney

Senior Vice-President and Chief Legal Officer

NI 43-101, mineral reserves, mineral resources

3 terms

NI 43-101 regulatory

"under National Instrument 43-101 – Standards of Disclosure for Mineral Projects"

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.

mineral reserves technical

"a change in mineral reserves or mineral resources"

Mineral reserves are the amounts of a metal or mineral that a company has identified and can legally and economically extract with current technology. Think of it like the usable fuel in a car’s tank rather than all the oil in the ground; reserves determine how long a mine can produce, help estimate future revenue and costs, and shape a company’s value and investment risk.

mineral resources technical

"a change in mineral reserves or mineral resources"

Mineral resources are naturally occurring concentrations of metals or other valuable materials in the earth that could be mined and sold, like pockets of useful ingredients inside a giant pantry. For investors they show the raw-material potential behind a mining project: bigger or higher-quality resources can mean more future revenue, while the cost, technical difficulty and regulatory hurdles determine how much of that value can actually be realized.

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

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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 November, 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 November 4, 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.

Exhibit 99.1

LOGO


NEWS RELEASE				Saskatoon
NEWS RELEASE				Saskatchewan
All amounts in Canadian dollars				Canada
unless specified otherwise

Cameco Reports Document Filing

November 4, 2026

Cameco Corporation (TSX: CCO; NYSE: CCJ) reported today that it filed a technical report for the McArthur River operation on a voluntary basis under National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”). The technical report is being filed to provide updated information relating to the McArthur River operation and not as a result of a change in mineral reserves or mineral resources that constitutes a material change in relation to Cameco. The technical report has been posted on our website and SEDAR+ at www.sedarplus.ca and on EDGAR on the SEC website at www.sec.gov. Our website, SEDAR+ and EDGAR are not part of this press release and are not incorporated by reference herein. Readers are encouraged to read the technical report in its entirety, including all qualifications, assumptions and exclusions therein.

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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