We have the option to redeem some or all of the notes at any time and from time to time, as described under the heading “Description of the Notes—Optional Redemption.” If a TaxCredit Event (as defined herein) occurs with respect to a series of notes, we may also redeem such series of notes, in whole but not in part, at a redemption price equal to 101% of the principalamount thereof plus accrued and unpaid interest to the redemption date. See “Description of the Notes—Right to Redeem Upon a Tax Credit Event.” Upon the occurrence of a change ofcontrol triggering event, you may require us to repurchase some or all of your notes of each series at 101% of their principal amount thereof, plus accrued and unpaid interest, if any, to, but We intend to use the net proceeds from this offering to repay existing indebtedness and for general corporate purposes. See “Use of Proceeds.” The notes will be our senior unsecured obligations ranking equally with all of our other unsecured debt and effectively junior to our future secured debt, if any, and structurallysubordinated to the debt and other liabilities (including trade payables) of our subsidiaries. The notes will be issued only in registered form in minimum denominations of $2,000 and integralmultiples of $1,000 in excess thereof. The underwriters expect to deliver the notes to purchasers in book-entry form on or about June 16, 2026. SMBCNikko Prospectus Supplement About this Prospectus SupplementIncorporation by ReferenceWhere You Can Find More InformationSummaryCompany InformationSummary Historical Consolidated Financial InformationThe OfferingRisk FactorsForward-Looking StatementsUse of ProceedsDescription of the NotesU.S. Federal Income Tax ConsiderationsUnderwritingLegal MattersIndependent Registered Public Accounting Firm The AES CorporationWhere You Can Find More InformationSpecial Note on Forward-Looking StatementsUse of ProceedsDescription of SecuritiesValidity of SecuritiesExperts Table of Contents ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement is part of a registration statement that we filed with the Securities and Exchange Commission (the “SEC”) utilizing a“shelf” registration process. Under this shelf registration process, we are offering to sell the notes using this prospectus supplement and theaccompanying prospectus. This prospectus supplement describes the specific terms of this offering. The accompanying prospectus gives more generalinformation, some of which may not apply to this offering. You should read this prospectus supplement together with the accompanying prospectus andthe documents incorporated by reference into this prospectus supplement and the accompanying prospectus before making a decision to invest in the INCORPORATION BY REFERENCE We have “incorporated by reference” into this prospectus supplement and the accompanying prospectus certain documents that we file with theSEC. This means that we can disclose important information to you by referring you to another document filed separately with the SEC. Thisinformation incorporated by reference is apart of this prospectus supplement and the accompanying prospectus, unless we provide you with differentinformation in this prospectus supplement or the information is modified or superseded by a subsequently filed document. Any information referred to in This prospectus supplement and the accompanying prospectus incorporate the documents listed below that we have previously filed with the SEC(other than, in each case, documents or information deemed to have been furnished and not filed in accordance with the SEC’s rules and regulations),which contain important information about us, our business, our financial condition and various important risks you should consider before investing in •our Annual Report onForm 10-Kfor the fiscal year ended December31, 2025 (the “Annual Report”), filed with the SEC on March2,2026;•our Quarterly Report onForm10-Qfor the quarter ended March31, 2026 (the “Quarterly Report”), filed with the SEC on May5, 2026; Any reports filed by us pursuant to Section13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) onor after the date of this prospectus supplement and before the completion of this offering of the notes will be deemed to be incorporated by referenceinto this prospectus supplement and the accompanying prospectus and will automatically update, where applicable, and supersede any informationcontained in this prospectus supplement or the accompanying prospectus or incorporated by reference into this prospectus supplement and the Table of Contents WHERE YOU CAN FIND MORE INFORMATION We file annual, quarterly and current reports, proxy statements and other information with the SEC. The SEC also maintains an internet site athttp://www.sec.gov, from which you can access our filings with the SEC. We maintain an internet site located at http://www.aes.com, which containsinformation pertaining