Ideal Power Inc 美股招股说明书（2026年5月18日版）

3,220,961 Shares of Common StockPre-Funded Warrants to Purchase up to 2,070,044 Shares of Common Stock We are offeringin a registered direct offering 3,220,961shares of our common stock, par value $0.001 per share, and pre-funded warrants to purchase up to an aggregate of 2,070,044 shares of common stock, or the pre-funded warrants, in lieu of sharesof common stock to those purchasers whose purchase of shares of common stock in this offering would result in the purchaser,together with its affiliates and certain related parties, beneficially owning more than 4.99% (or, at the election of the purchaser,9.99%) of our outstanding shares of common stock following the consummation of this offering. Subject to limited exceptions, aholder of pre-funded warrants will not have the right to exercise any portion of its pre-funded warrants if the holder, together withits affiliates, would beneficially own in excess of 4.99% (or, at the election of the holder, such limit may be increased to up to This prospectus supplement and the accompanying prospectus also relate to the offering of the shares of common stockissuable upon exercise of the pre-funded warrants in this offering. We collectively refer to the shares of common stock and pre- Our common stock is listed on The Nasdaq Capital Market (“Nasdaq”) under the symbol “IPWR.” On May 14, 2026, the lastreported sale price of our common stock on Nasdaq was $7.38 per share. There is no established public trading market for the pre-funded warrants, and we do not expect a market to develop. We do not intend to apply to list the pre-funded warrants on any We have engaged Titan Partners Group LLC, a division of American Capital Partners, LLC, as our exclusive placement agentfor this offering (the “placement agent”). The placement agent is not purchasing or selling any securities offered by this prospectussupplement and the accompanying prospectus but will use their reasonable best efforts to arrange for the sale of the securitiesoffered. See “Plan of Distribution.” This offering is expected to close on or about May 18, 2026, subject to customary closing Table of Contents Investing in our securities involves risks. See“Risk Factors”on pageS-4of this prospectus supplement, on page4ofthe accompanying prospectus and in the documents which are incorporated by reference herein and therein. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved ofthese securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any (1)We have agreed to pay the placement agent a cash fee of 7.0% of the aggregate gross proceeds raised in connection withthe offering. We have also agreed to reimburse the placement agent for certain of their expenses. See “Plan of Distribution”for additional information regarding the compensation payable to the placement agent.(2)The amount of the offering proceeds to us presented in this table does not include proceeds from the exercise of the pre- Delivery of the securities is expected to be made on or about May 18, 2026. Titan Partners a division of American Capital Partners The date of this prospectus supplement isMay 14, 2026. ABOUT THIS PROSPECTUS SUPPLEMENTCAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTSPROSPECTUS SUPPLEMENT SUMMARYRISK FACTORSUSE OF PROCEEDSCAPITALIZATIONDILUTIONDIVIDEND POLICYDESCRIPTION OF SECURITIESMATERIAL UNITED STATES FEDERAL INCOME TAX CONSEQUENCESPLAN OF DISTRIBUTIONLEGAL MATTERSEXPERTSWHERE YOU CAN FIND MORE INFORMATIONINFORMATION INCORPORATED BY REFERENCE Table of Contents ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying prospectus are part of a registration statement on FormS-3 under theSecurities Act of 1933, as amended (the “Securities Act”), that we filed with the Securities and Exchange Commission (the “SEC”)using the “shelf” registration process. This document is in two parts. The first part is this prospectus supplement, including thedocumentsincorporated by reference herein,which describes the specific terms of this offering.The second part,theaccompanying prospectus, including the documents incorporated by reference therein, provides more general information. We urgeyou to carefully read this prospectus supplement and the accompanying prospectus, and the documents incorporated by referenceherein and therein, before buying any of the securities being offered under this prospectus supplement. This prospectus supplementmay add to or update information contained in the accompanying prospectus and the documents incorporated by reference therein.To the extent that any statement we make in this prospectus supplement is inconsistent with statements made in the accompanying We have not, and the placement agent has not, authorized anyone to provide any information or to make anyrepresentations other than those contained in this prospectus supplement, the accompanying prospectu