EX-32.1 9 tsvt-q4202210xkexhibit3211.htm EX-32.1
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 2seventy bio, Inc. (the “Company”) for the year ended December 31, 2022, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), each of the undersigned officers of the Company hereby certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, to his knowledge, 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.

Dated: March 16, 2023 |  | /s/ Chip Baird |
|  | Chip Baird |
|  | Chief Financial Officer
|  | (Principal Financial Officer and Principal Accounting Officer)
Dated: March 16, 2023 |  | /s/ Nick Leschly |
|  | Nick Leschly |
|  | Chief Executive Officer
|  | (Principal Executive Officer)