燃料电池能源美股招股说明书(2026-07-07版)

$200,000,000 FuelCell Energy, Inc. Common Stock We are offering $200,000,000 of shares of our common stock. Our common stock is listed on The Nasdaq Global Market under the symbol “FCEL.” On July 6, 2026,the last reported sale price for our common stock was $29.73 per share. Investing in our common stock involves a high degree of risk. You should read thisprospectus supplement and the accompanying prospectus carefully before you make yourinvestment decision. See “Risk Factors” beginning on pageS-4of this prospectus supplement,as well as the documents we file with the Securities and Exchange Commission that areincorporated by reference in this prospectus supplement and in the accompanyingprospectus, including our most recent Annual Report on Form 10-K and any subsequentlyfiled Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, for moreinformation. Neither the Securities and Exchange Commission nor any state securities commission has approved ordisapproved of these securities or determined if this prospectus supplement or the accompanying prospectus istruthful or complete. Any representation to the contrary is a criminal offense. Per ShareTotalPublic offering price$$Underwriting discounts and commissions$$Proceeds, before expenses, to us$$(1) (1)See the section entitled “Underwriting” for a description of the compensation payable to theunderwriters. We have granted the underwriters an option for a period of 30days from the date of this prospectussupplement to purchase an additional $30,000,000 of shares of our common stock. If the underwritersexercise the option in full, the total underwriting discounts and commissions payable by us will be$and the total proceeds to us, before expenses, will be $. The underwriters expect to deliver the shares of common stock against payment on or about, 2026. Joint Book-Running Managers , 2026. TABLE OF CONTENTS Prospectus Supplement ABOUT THIS PROSPECTUS SUPPLEMENT AND PROSPECTUSS-iiCAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTSS-iiiPROSPECTUS SUPPLEMENT SUMMARYS-1THE OFFERINGS-3RISK FACTORSS-4USE OF PROCEEDSS-6CAPITALIZATIONS-7DILUTIONS-9DESCRIPTION OF CAPITAL STOCKS-11MATERIAL UNITED STATES FEDERAL INCOME TAX CONSIDERATIONSS-18UNDERWRITINGS-23LEGAL MATTERSS-29EXPERTSS-29WHERE YOU CAN FIND ADDITIONAL INFORMATIONS-29 ABOUT THIS PROSPECTUS1FORWARD-LOOKING STATEMENTS1INCORPORATION BY REFERENCE2OUR COMPANY3RISK FACTORS4USE OF PROCEEDS4THE SECURITIES WE MAY OFFER4DESCRIPTION OF CAPITAL STOCK5DESCRIPTION OF DEBT SECURITIES12DESCRIPTION OF WARRANTS20DESCRIPTION OF UNITS21SELLING SECURITY HOLDERS22PLAN OF DISTRIBUTION23LEGAL MATTERS25EXPERTS25WHERE YOU CAN FIND ADDITIONAL INFORMATION25 We are offering to sell, and are seeking offers to buy, the securities only in jurisdictions where such offersand sales are permitted. The distribution of this prospectus supplement and the accompanying prospectus andthe offering of the securities in certain jurisdictions may be restricted by law. Persons outside the United Stateswho come into possession of this prospectus supplement and the accompanying prospectus must informthemselves about and observe any restrictions relating to the offering of the securities and the distribution ofthis prospectus supplement and the accompanying prospectus outside the United States. This prospectussupplement and the accompanying prospectus do not constitute, and may not be used in connection with, anoffer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement and theaccompanying prospectus to or by any person in any jurisdiction in which it is unlawful for such person toreceive or make such an offer or solicitation. ABOUT THIS PROSPECTUS SUPPLEMENT AND PROSPECTUS This document consists of two parts. The first part is this prospectus supplement, which describes thespecific terms of the securities we are offering. The second part is the accompanying prospectus, whichgives more general information, some of which may not apply to this offering. This prospectus supplementand the information incorporated by reference in this prospectus supplement may add to, update and changeinformation contained in, or incorporated by reference into, the accompanying prospectus. To the extentthere is a conflict between the information contained in this prospectus supplement, on the one hand, or inany document incorporated by reference herein that was filed with the Securities and Exchange Commission(“SEC”) before the date of this prospectus supplement, on the other hand, you should rely on theinformation in this prospectus supplement. If any statement in one of these documents is inconsistent with astatement in another document having a later date, for example, a document incorporated by reference inthis prospectus supplement or the accompanying prospectus, the statement in the document having the laterdate modifies or supersedes the earlier statement. The accompanying prospectus is part of a regi