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 Stagwell Inc. (the “Company”) on Form 10-Q for the quarter ended March 31, 2024, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Mark Penn, Chairman and Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, to my knowledge, that:

(1)The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; 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: May 2, 2024
/s/ MARK PENN
By:	Mark Penn
Title:	Chairman and Chief Executive Officer
	(Principal Executive Officer)