Fiserv (FI) 10-K 2023 FY Annual report

EXHIBIT 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Annual Report on Form 10-K of Fiserv, Inc. (the “Company”) for the year ended December 31, 2023 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), Frank J. Bisignano, as Chairman, President and Chief Executive Officer of the Company, and Robert W. Hau, as Chief Financial Officer of the Company, each hereby certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that to the best of his knowledge:

(1)The Report fully complies with the requirements of Section 13(a) of the Securities Exchange Act of 1934; and

(2)The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

By:	/s/ Frank J. Bisignano
	Frank J. Bisignano
	Chairman, President and Chief Executive Officer
	February 22, 2024
By:	/s/ Robert W. Hau
	Robert W. Hau
	Chief Financial Officer
	February 22, 2024