Discover Financial Services (DFS) 10-Q 2023 Q3 Quarterly 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 Quarterly Report of Discover Financial Services (the "Company") on Form 10-Q for the period ended September 30, 2023, as filed with the Securities and Exchange Commission (the "Report"), each of John B. Owen, Interim Chief Executive Officer and President of the Company, and John T. Greene, Executive Vice President and Chief Financial Officer of the Company, certifies, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

1.The Report fully complies with the requirements of Section 13(a) or 15(d) 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.

Date: October 26, 2023

/s/ JOHN B. OWEN

John B. Owen

Interim Chief Executive Officer and President

Date:October 26, 2023

/s/ JOHN T. GREENE

John T. Greene

Executive Vice President, Chief Financial Officer