X0306 4 2021-11-08 0 0001370880 Mandiant, Inc. MNDT 0001201177 CODD RONALD E F C/O MANDIANT, INC. 601 MCCARTHY BLVD. MILPITAS CA 95035 1 0 0 0 Common Stock 2021-11-08 4 M 0 40000 2.48 A 45075 D Common Stock 2021-11-08 4 S 0 40000 18.0491 D 5075 D Common Stock 136625 I See Footnote Employee Stock Option (right to buy) 2.48 2021-11-08 4 M 0 40000 0.00 D 2022-09-11 Common Stock 40000 78000 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on September 11, 2021. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.00 to $18.14, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (2). Shares held of record by the Codd Revocable Trust Dtd March 6, 1998, for which the Reporting Person serves as a trustee. The shares subject to this option are fully vested and exercisable. Ashlyn Perry, Attorney-in-Fact 2021-11-10