Material Event (Form 8-K)

On September 11, 2025, Capital One Financial Corporation (the "Company") closed the public offering of $1,250,000,000 aggregate principal amount of its 4.493% Fixed-to-FloatingRate Senior Notes due 2031 (the "2031 Fixed-to-FloatingRate Notes") and $1,500,000,000 aggregate principal amount of its 5.197% Fixed-to-FloatingRate Senior Notes due 2036 (the "2036 Fixed-to-FloatingRate Notes" and, together with the 2031 Fixed-to-FloatingRate Notes, the "Notes"), pursuant to an underwriting agreement (the "Underwriting Agreement"), dated September 8, 2025, with Citigroup Global Markets Inc., Goldman Sachs & Co. LLC, Morgan Stanley & Co. LLC, RBC Capital Markets, LLC and Capital One Securities, Inc., as representatives of the several underwriters listed therein. The Notes were issued pursuant to a Senior Indenture dated as of November 1, 1996 between the Company and The Bank of New York Mellon Trust Company, N.A., formerly known as The Bank of New York Trust Company, N.A. (as successor to Harris Trust and Savings Bank), as Indenture Trustee (the "Trustee"), as supplemented by the First Supplemental Indenture dated as of November 2, 2021 between the Company and the Trustee. The Notes have been registered under the Securities Act of 1933, as amended, by a registration statement on Form S-3(File No. 333-277813).

The foregoing description of the Underwriting Agreement, Notes and other documents relating to this transaction does not purport to be complete and is qualified in its entirety by reference to the full text of these securities and documents, forms or copies of which are attached as exhibits to this Current Report on Form 8-Kand are incorporated herein by reference.