Filed pursuant to Rule 424(b)(3)
Registration No. 333-290723
PROSPECTUS SUPPLEMENT No. 8
(to Prospectus dated October 27, 2025)
USA RARE EARTH, INC.

This prospectus supplement updates, amends and
supplements the prospectus dated October 27, 2025 (the “Prospectus”), which forms a part of our Registration Statement on
Form S-1 (Registration No. 333-290723). Capitalized terms used in this prospectus supplement and not otherwise defined herein have the
meanings specified in the Prospectus.
This prospectus supplement is being filed to update,
amend and supplement the information included in the Prospectus with the information contained in:
| ● | our Current Report on Form 8-K filed with the SEC on March 12, 2026, excluding Item 7.01 and Exhibit 99.1,
which is set forth below. |
This prospectus supplement is not complete without
the Prospectus. This prospectus supplement should be read in conjunction with the Prospectus, which is to be delivered with this prospectus
supplement, and is qualified by reference thereto, except to the extent that the information in this prospectus supplement updates or
supersedes the information contained in the Prospectus. Please keep this prospectus supplement with your Prospectus for future reference.
USA Rare Earth, Inc.’s Common Stock is listed
on the Nasdaq Stock Market LLC under the symbol “USAR”. On March 11, 2026, the closing price of our Common Stock was $21.09
per share.
We are an “emerging growth company”
and a “smaller reporting company” as such terms are defined under the federal securities laws and, as such, are subject to
certain reduced public company reporting requirements.
Investing in our securities involves a high
degree of risk. You should review carefully the risks and uncertainties described under the heading “Risk Factors”
of the Prospectus, and under similar headings in any amendments or supplements to the Prospectus.
Neither the SEC nor any state securities commission
has approved or disapproved of these securities or determined if the Prospectus or this prospectus supplement is truthful or complete.
Any representation to the contrary is a criminal offense.
The date of this prospectus supplement is March
12, 2026.
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 OR 15(d)
of The Securities Exchange Act of 1934
Date of Report (Date of earliest event reported):
March 9, 2026

USA Rare Earth, Inc.
(Exact Name of Registrant as Specified in its
Charter)
| Delaware |
|
001-41711 |
|
98-1720278 |
(State or Other Jurisdiction
of Incorporation) |
|
(Commission File Number) |
|
(I.R.S. Employer
Identification No.) |
100 W. Airport Road, Stillwater, OK 74075
(Address of Principal Executive Offices) (Zip
Code)
(813) 867-6155
(Registrant’s telephone number, including
area code)
Not applicable
(Former Name or Former Address, if Changed Since
Last Report)
Check the appropriate box below if the Form 8-K
filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:
| ☐ |
Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) |
| ☐ |
Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) |
| ☐ |
Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) |
| ☐ |
Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) |
Securities registered pursuant to Section 12(b) of the Act:
| Title of each class |
|
Trading Symbol(s) |
|
Name of each exchange on which registered |
| Common Stock, par value $0.0001 |
|
USAR |
|
The Nasdaq Stock Market LLC |
Indicate by check mark whether the registrant
is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the
Securities Exchange Act of 1934 (§240.12b-2 of this chapter).
Emerging growth company ☒
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. ☐
Item 5.02. Departure of Directors
or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensation Arrangements of Certain Officers.
Resignation of Director; Appointment
of Director
On March
9, 2026, Tready Smith resigned from the Board of Directors (the “Board”) of USA Rare Earth, Inc. (the “Company”),
and the Board subsequently appointed Thomas Caulfield as a director of the Company, filling the vacancy resulting from Ms. Smith’s
resignation, such that the Board continues to have a total of eight directors serving on the Board. Additionally, the Board appointed
Dr. Caulfield to serve as a member of the Compensation Committee and the Nominating and Corporate Governance Committee of the Board, effective
upon his appointment to the Board. Ms. Smith’s resignation did not result from any disagreement with the Company.
Dr. Caulfield is the Executive Chairman of GlobalFoundries
(Nasdaq: GFS) and previously served, from 2018 to 2025 as the President and Chief Executive Officer of GlobalFoundries. Dr. Caulfield
also serves as a board member of Sandisk Corp. The Board has determined that Dr. Caulfield qualifies
as an independent director for service on the Board and the committees to which he was assigned under Nasdaq Listing Rules. Dr. Caulfield
will participate in the Company’s standard director compensation program as described in the Company's Registration Statement on
Form S-1, which was filed with the Securities and Exchange Commission on February 3, 2026, except that Dr. Caufield’s compensation
will be awarded solely in equity and not in cash, unless otherwise elected by Dr. Caufield.
Item 7.01 Regulation FD Disclosure.
On March
12, 2026, the Company issued a press release announcing both the appointment of Dr. Caufield and resignation of Ms. Smith. A copy of the
press release is furnished herewith as Exhibit 99.1 and is incorporated by reference herein.
The information
provided under this Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.1, is “furnished” and shall not be
deemed “filed” with the SEC or incorporated by reference in any filing under the Securities Exchange Act of 1934, as amended
(the “Exchange Act”).
Item 8.01. Other Events.
On March
9, 2026, the Board determined that the date for its 2026 Annual Meeting of Shareholders will be June 3, 2026. The time and other
meeting details for the 2026 Annual Meeting of Shareholders will be set forth in the Company’s proxy statement for the 2026 Annual
Meeting, which will be filed with the SEC prior to the 2026 Annual Meeting.
Because
this will be the Company’s first annual meeting of shareholders, shareholders who wish to present a proposal to be considered
for inclusion in the Company’s proxy materials pursuant to Rule 14a-8 under the Exchange Act for the 2026 Annual Meeting of
Shareholders must submit such proposal to the Company’s Secretary by April 1, 2026, which the Company has determined to be a
reasonable time before the Company expects to begin printing and sending the proxy materials. Any such proposal must meet the
requirements set forth in the rules and regulations of the Securities and Exchange Commission.
Item 9.01. Financial Statements and Exhibits.
(d) Exhibits:
The following exhibits are attached with this current
report on Form 8-K:
| Exhibit No. |
|
Description |
| 99.1 |
|
Press Release, dated March 12, 2026. |
| 104 |
|
Cover Page Interactive Data File (embedded within the Inline XBRL document) |
SIGNATURES
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 hereunto
duly authorized.
| |
USA Rare Earth, Inc. |
| |
|
|
| Date: March 12, 2026 |
By: |
/s/ Valerie Ford Jacob |
| |
|
Chief Legal Officer |