SEC Form 424B3 filed by SunPower Inc.

SUNPOWER INC.

Up to 48,521,163 Shares of Common Stock

This prospectus supplement supplements the prospectus dated January 23, 2026 (as amended or supplemented, the “prospectus”), which forms a part of our registration statement on Form S-1 (No. 333-292713). This prospectus supplement is being filed to update and supplement the information in the prospectus with the information contained in our Current Report on Form 8-K filed with the Securities and Exchange Commission on March 30, 2026 (the “Current Report”). Accordingly, we have attached the Current Report to this prospectus supplement.

The prospectus and this prospectus supplement relate to the potential offer and sale of up to 48,521,163 shares of our common stock, par value $0.0001 per share (the “common stock”), by White Lion Capital, LLC (“White Lion” or the “Selling Securityholder”).

The shares of common stock to which the prospectus and this prospectus supplement relate may be issued to White Lion pursuant to the Common Stock Purchase Agreement dated July 16, 2024 between us and White Lion, as amended by Amendment No. 1 to the Common Stock Purchase Agreement dated July 24, 2024, Amendment No. 2 to the Common Stock Purchase Agreement dated August 14, 2024, and Amendment No. 3 to the Common Stock Purchase Agreement dated January 11, 2026 (as amended, the “White Lion Purchase Agreement”), establishing an equity line of credit. Such shares of our common stock include up to 48,521,163 shares of common stock that we may elect, in our sole discretion, to issue and sell to White Lion from time to time during the commitment period under the White Lion Purchase Agreement. See “The White Lion Transaction” and “Selling Securityholder” in the prospectus for more information regarding the White Lion Purchase Agreement and the Selling Securityholder.

The actual number of shares of our common stock issuable to White Lion will vary depending on the then-current market price of shares of our common stock sold to the Selling Securityholder under the White Lion Purchase Agreement and are subject to the further limitations set forth in the White Lion Purchase Agreement.

We are not selling any securities under the prospectus or this prospectus supplement and will not receive any of the proceeds from the sale of shares of common stock by the Selling Securityholder. However, we may receive proceeds of up to approximately $48.5 million from the sale of our common stock to the Selling Securityholder pursuant to the White Lion Purchase Agreement after the date of the prospectus (assuming the shares are sold at a price of $1.00 per share). The actual proceeds from White Lion under the White Lion Purchase Agreement may be less than this amount depending on the number of shares of our common stock sold and the price at which the shares of our common stock are sold.

The Selling Securityholder may sell or otherwise dispose of the shares of common stock described in the prospectus in a number of different ways and at varying prices. See “Plan of Distribution” in the prospectus for more information about how the Selling Securityholder may sell or otherwise dispose of the shares of common stock being registered pursuant to the prospectus. The Selling Securityholder is an “underwriter” within the meaning of Section 2(a)(11) of the Securities Act of 1933, as amended.

The Selling Securityholder will pay all brokerage fees and commissions and similar expenses attributable to the sales of common stock by it. We will pay the expenses (except brokerage fees and commissions and similar expenses) incurred in registering the shares of common stock offered by the prospectus, including legal and accounting fees. See “Plan of Distribution” in the prospectus.

Our common stock and our public warrants are listed on The Nasdaq Stock Market under the symbols “SPWR” and “SPWRW,” respectively. On March 30, 2026, the last reported sales price of our common stock was $1.22 per share, and the last reported sales price of our public warrants was $0.24 per public warrant.

This prospectus supplement should be read in conjunction with the prospectus, including any amendments or supplements thereto, which is to be delivered with this prospectus supplement. This prospectus supplement is qualified by reference to the prospectus, including any amendments or supplements thereto, except to the extent that the information in this prospectus supplement updates and supersedes the information contained therein.

This prospectus supplement is not complete without, and may not be delivered or utilized except in connection with, the prospectus, including any amendments or supplements thereto.

We are an “emerging growth company” as defined under U.S. federal securities laws and, as such, have elected to comply with reduced public company reporting requirements. The prospectus and this prospectus supplement comply with the requirements that apply to an issuer that is an emerging growth company.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described in the section titled “Risk Factors” beginning on page 8 of the prospectus, and under similar headings in any amendments or supplements to the prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities, or passed upon the accuracy or adequacy of the prospectus or this prospectus supplement. Any representation to the contrary is a criminal offense.

Prospectus Supplement dated March 31, 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 25, 2026

SunPower Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (510) 270-2507

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 obligations of the registrant under any of the following provisions:

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

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; Compensatory Arrangements of Certain Officers.

Approval of Second Amendment to 2023 Equity Incentive Plan

On March 25, 2026, SunPower Inc. (the “Company”) held a Special Meeting of Stockholders (the “Special Meeting”). At the Special Meeting, the Company’s stockholders approved the Second Amendment (the “Second Amendment”) to the Company’s 2023 Equity Incentive Plan, as amended (as amended, the “2023 Plan”). The Second Amendment increases the total number of shares of common stock of the Company, $0.0001 par value per share (the “Common Stock”), reserved for issuance under the 2023 Plan to 44,573,109 shares of Common Stock.

The foregoing description of the Second Amendment is qualified in its entirety by reference to the Second Amendment, filed as Exhibit 10.1 hereto.

Item 5.07 Submission of Matters to a Vote of Security Holders.

The Company held the Special Meeting on March 25, 2026. Set forth below are the final results of the voting with respect to each matter acted upon at the Special Meeting. The related proposals are described in further detail in the Company’s definitive proxy statement filed with the U.S. Securities and Exchange Commission on February 20, 2026 (the “Proxy Statement”).

Proposal 1 - To approve, for purposes of complying with Nasdaq Listing Rule 5635(a), the issuance of shares of Common Stock as additional consideration pursuant to the Membership Interest Purchase Agreement, dated as of September 21, 2025, by and among SunPower Inc., Complete Solar, Inc., Chicken Parm Pizza LLC and Sunder Energy LLC in excess of 3,333,334 shares of Common Stock

The Company’s stockholders approved Proposal 1.

Proposal 2 – To approve, for purposes of complying with Nasdaq Listing Rule 5635(a), the issuance of shares of Common Stock that may be issuable upon the conversion of an additional $22,225,000 aggregate principal amount of the Company’s 7.00% Convertible Senior Notes due 2029 (the “7.00% Notes” and such additional $22,225,000 aggregate principal amount of 7.00% Notes, the “Additional 7.0% Notes”), which Additional 7.0% Notes may become issuable by the Company following the exercise of an additional purchase option for the Additional 7.0% Notes pursuant to the various Note Purchase Agreements, dated as of September 21, 2025, between the Company and the purchasers party thereto

The Company’s stockholders approved Proposal 2.

Proposal 3 – To approve, for purposes of complying with Nasdaq Listing Rule 5635(a), the issuance of shares of Common Stock as post-closing consideration pursuant to the Membership Interest Purchase Agreement, dated as of November 21, 2025, by and among SunPower Inc., Ambia Holdings, Inc. and Ambia Energy, LLC in excess of 16,620,910 shares of Common Stock

The Company’s stockholders approved Proposal 3.

Proposal 4 – To approve, for purposes of complying with Nasdaq Listing Rule 5635(d), the increase of the aggregate commitment amount under the Amended White Lion Purchase Agreement (as defined in the Proxy Statement) from $30.0 million to $55.0 million shares of Common Stock

The Company’s stockholders approved Proposal 4,

Proposal 5 – To approve, for purposes of complying with Nasdaq Listing Rule 5635(d), the issuance of shares of Common Stock (a) pursuant to the Standby Equity Purchase Agreement, dated January 27, 2026 between YA II PN, Ltd. (“Yorkville”), and SunPower Inc. (the “Yorkville Purchase Agreement”) and (b) upon the conversion of convertible promissory notes issued to Yorkville in connection with the Yorkville Purchase Agreement, in an amount that may be equal to or exceed 20% of the Common Stock outstanding as of January 27, 2026

The Company’s stockholders approved Proposal 5.

Proposal 6 – To approve an amendment to the Company’s 2023 Equity Incentive Plan, as amended, to reserve an additional 8,000,000 shares of Common Stock for issuance under the 2023 Equity Incentive Plan, as amended

The Company’s stockholders approved Proposal 6.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

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.

Exhibit 10.1

Second Amendment

to SunPower Inc.

2023 Equity Incentive Plan, As Previously Amended

This Second Amendment (the “Amendment”) to the SunPower Inc. 2023 Equity Incentive Plan, as previously amended (the “Plan”), is made by SunPower Inc., a Delaware corporation (the “Company”), effective as of the date of its approval by the stockholders of the Company at the Company’s 2026 Special Meeting of Stockholders.

This Amendment was approved by the Company’s Board of Directors on February 10, 2026.

1. Amendments.

a. Section 2(a) of the Plan is hereby amended and restated in its entirety to read as follows:

“(a) Shares Reserve. Subject to adjustment in accordance with Section 2(c) and any adjustments as necessary to implement any Capitalization Adjustments, the aggregate number of shares of Common Stock that may be issued pursuant to Awards will not exceed 44,573,109 shares of Common Stock (which number of shares of Common stock includes additional shares of Common Stock available for issuance as a result of automatic increases thereto through and including January 1, 2026, as contemplated by the next sentence). In addition, subject to any adjustments as necessary to implement any Capitalization Adjustments, such aggregate number of shares of Common Stock will automatically increase on January 1 of each year for a period of ten years commencing on January 1, 2024 and ending on (and including) January 1, 2033, in an amount equal to 4% of the total number of shares of Common Stock outstanding on December 31 of the preceding year; provided, however, that the Board may act prior to January 1st of a given year to provide that the increase for such year will be a lesser number of shares of Common Stock.”

b. Section 2(b) of the Plan is hereby amended and restated in its entirety to read as follows:

“(b) Aggregate Incentive Stock Option Limit. Notwithstanding anything to the contrary in Section 2(a) and subject to any adjustments as necessary to implement any Capitalization Adjustments, the aggregate maximum number of shares of Common Stock that may be issued pursuant to the exercise of Incentive Stock Options is 44,573,109 shares.”

2. Continued Effect. Except as set forth herein, the Plan shall remain unchanged and in full force and effect, and the forms of stock option award agreements, restricted stock units award agreements and any outstanding award agreements under the Plan shall effectively adopt the amendments herein, as applicable.