5E Advanced Materials, Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended June 30,2025

or

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from to

Commission File Number 001-41279

(Exact name of Registrant as specified in its Charter)

Registrant’s telephone number, including area code: (442)221-0225

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes☐ No ☒

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes☐ No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☒

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements.☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes☐ No☒

The aggregate market value of the voting and non-voting common equity held by non-affiliates of the registrant was approximately$37.2 million as of

December 31, 2024 (based on the last reported sale price of such stock on the Nasdaq Global Select Market on that date).

As of September 28, 2025, the number of shares outstanding of the registrant’s common stock was 22,444,587.

TABLE OF CONTENTS

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Selected Definitions

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“5E Boron Americas” refers to 5E Boron Americas, LLC (f/k/a Fort Cady (California) Corporation).

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“ABR” refers to American Pacific Borates Limited, a company incorporated under the laws of Australia.

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“ASX” refers to the Australian Securities Exchange.

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“Board” refers to the 5E Advanced Materials, Inc. Board of Directors.

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“Bylaws” refers to the Amended and Restated Bylaws of 5E Advanced Materials, Inc.

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“CDI” refers to a CHESS Depositary Interest.

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“CERLA” refers to the Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended.

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“Certificate of Incorporation” refers to the Amended and Restated Certificate of Incorporation of 5E Advanced Materials, Inc., as amended.

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“Common Stock” refers to the Company’s common stock, par value $0.01 per share.

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“Company” refers to 5E Advanced Materials, Inc., a Delaware corporation.

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“Corporations Act” refers to the Australian Corporations Act, 2001 (Cth).

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“EPA” refers to the U.S. Environmental Protection Agency.

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“EPC” refers to engineering, procurement and construction.

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“Exchange Act” refers to the Exchange Act of 1934, as amended.

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“FEL” refers to front end loading, a stage gated project management system (with a number to the corresponding stage, e.g., FEL-1, FEL-2, FEL-3.)

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“LCE” refers to lithium carbonate equivalents.

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“MST” refers to million short tons.

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“Nasdaq” refers to the Nasdaq Global Select Market.

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“ppm” refers to parts per million.

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“Preliminary Feasibility Study” or “PFS” refers to the Preliminary Feasibility Study and Technical Report Study, dated August 7, 2025, included as Exhibit 96.1 to this Annual Report.

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“Project” refers to the 5E Boron Americas (Fort Cady) Complex.

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“Scheme” refers to a statutory Scheme of Arrangement under Australian law under Part 5.1 of the Corporations Act.

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“SEC” refers to the U.S. Securities and Exchange Commission.

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“Securities Act” refers to the Securities Act of 1933, as amended.

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“SSF” refers to the current Small-Scale Facility.

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“QPs” refers to Qualified Persons, as defined by SEC Regulation S-K 1300.

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