X0306 4 2022-05-15 0 0001370880 Mandiant, Inc. MNDT 0001855154 Watters John P. C/O MANDIANT, INC. 11951 FREEDOM DRIVE, 6TH FLOOR RESTON VA 20190 0 1 0 0 President & COO Common Stock 2022-05-15 4 F 0 10453 21.78 A 394298 D Common Stock 20000 I See footnote Common Stock 35000 I See footnote This transaction is not a sale of shares by the Reporting Person. Instead, the shares were withheld by the Issuer, to satisfy withholding taxes in connection with the vesting on May 15, 2022 of restricted stock units held by the Reporting Person. Shares held of record by JPW Advisory, Inc., for which the Reporting Person serves as the sole officer and director. Shares held of record by Dorset Investment Partners, Ltd., a family limited partnership of which the Reporting Person and his spouse are general partners. The Reporting Person disclaims beneficial ownership of all shares held by the family limited partnership, except to the extent of his pecuniary interest therein. Richard Meamber, Attorney-in-Fact 2022-05-17