X0306 4 2022-06-14 0 0001010086 SIGA TECHNOLOGIES INC SIGA 0001835535 Nemirovsky Julian C/O SIGA TECHNOLOGIES, INC. 31 EAST 62ND STREET NEW YORK NY 10065 1 0 0 0 Common Stock, par value $.0001 per share 2022-06-14 4 M 0 22831 A 22831 D Common Stock, par value $.0001 per share 2022-06-14 4 D 0 6849 10.26 D 15982 D Restricted Stock Units 2022-06-14 4 M 0 22831 0.00 D Common Stock, par value $.0001 per share 22831 0 D Restricted Stock Units 2022-06-14 4 A 0 14620 0.00 A Common Stock, par value $.0001 per share 14620 14620 D Restricted stock units ("RSUs") represent contingent rights to receive common stock of SIGA Technologies, Inc. (the "Company") on a one-for-one basis. Reflects RSUs that were cash-settled, per the terms of the compensation program for Board Directors and as noted on the Form 4 filed on June 17, 2021. Partial cash-settlement of RSUs under the Board compensation program is designed to address tax obligations in connection with the vesting of RSUs. The RSUs were granted on June 15, 2021, and fully vested on the date of the Company's 2022 annual meeting of stockholders. RSUs represent contingent rights to receive common stock of the Company on a one-for-one basis, of which up to 4,386 RSUs are expected to settle in cash value thereof but may be settled in shares at the discretion of the board of directors. The RSUs fully vest on the date of the Company's 2023 annual meeting of stockholders. /s/ Kevin Buckley, as Attorney-in-Fact 2022-06-15