Stem Inc-A 美股招股说明书（2026年3月6日版）

PROSPECTUS SUPPLEMENTFiled Pursuant to Rule 424(b)(5)(To Prospectus dated November 26, 2025)Registration No. 333-291820 STEM, INC. Up to $30,000,000 Common Stock We have entered into an Open Market Sale Agreement sale of shares of our common stock, par value $0.0001 per share (“Common Stock”), offered by this prospectus supplement and theaccompanying prospectus. In accordance with the terms of such Sale Agreement, and pursuant to this prospectus supplement and theaccompanying prospectus, we may offer and sell shares of our Common Stock having an aggregate offering price of up to $30,000,000from time to time through the Sales Agent acting as our agent. Our Common Stock is listed on the New York Stock Exchange (“NYSE”) under the symbol “STEM.” The last reported sale price ofour Common Stock on the NYSE on March 5, 2026 was $12.18 per share. We recommend that you obtain current market quotations Sales of our Common Stock, if any, under this prospectus supplement and the accompanying prospectus will be made in sales deemedto be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended (the“Securities Act”). The Sales Agent is not required to sell any specific number or dollar amount of securities but will act as our sales The compensation to the Sales Agent for sales of Common Stock sold pursuant to the Sale Agreement will be up to 3.0% of the grossproceeds of any shares of Common Stock sold under the Sale Agreement. In connection with the sale of the Common Stock on ourbehalf, the Sales Agent will be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation of theSales Agent will be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and You should carefully read this prospectus supplement and the accompanying prospectus, together with the documents we incorporateby reference, before you invest in our Common Stock. We are a smaller reporting company as defined in Rule 12b-2 promulgated under the Exchange Act. As such, we have elected to relyon certain reduced public company disclosure requirements. See “Prospectus Supplement Summary—Implications of Being a Smaller Investing in our Common Stock involves risks. See “Risk Factors” in this prospectus supplement, starting on pageS-4. Youshould also consider the risk factors described in the documents incorporated by reference into this prospectus supplement Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of thesesecurities or passed upon the adequacy or accuracy of this prospectus supplement. Any representation to the contrary is a ______________________________Jefferies March 6, 2026 PROSPECTUS SUPPLEMENT ABOUT THIS PROSPECTUS SUPPLEMENTS-iiWHERE YOU CAN FIND MORE INFORMATIONS-ivINCORPORATION OF CERTAIN INFORMATION BY REFERENCES-ivCAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTSS-viPROSPECTUS SUPPLEMENT SUMMARYS-1RISK FACTORSS-3 ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement is a part of a registration statement on Form S-3 we filed with the Securities and ExchangeCommission (the “SEC” or the “Commission”) using a “shelf” registration process. Under this shelf registration process, we may fromtime to time sell shares of our Common Stock, preferred stock, warrants, rights and/or units consisting of some or all of thesesecurities, in any combination, having an aggregate offering price of up to $200.0 million. Under this prospectus supplement, we may We provide information to you about this offering of shares of our Common Stock in two separate documents: (1) this prospectussupplement, which describes the specific details regarding this offering; and (2) the accompanying prospectus, which provides generalinformation, some of which may not apply to this offering. Generally, when we refer to this “prospectus,” we are referring to bothdocuments combined. If information in this prospectus supplement is inconsistent with the accompanying prospectus, you should relyon this prospectus supplement. To the extent there is a conflict between the information contained in this prospectus supplement, on You should rely only on the information contained in or incorporated by reference in this prospectus supplement. Neither we northe Sales Agent have authorized anyone to provide you with different information. If anyone provides you with different orinconsistent information, you should not rely on it. We are not, and the Sales Agent is not, making an offer to sell these securities inany jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus This prospectus supplement, the accompanying prospectus and the information incorporated herein or therein by referencecontains market data, industry statistics and other data that have been obtained or compiled from information made available by