X0508 4 2026-02-20 0001666134 BLACKLINE, INC. BL 0001688365 Tucker Therese 21300 VICTORY BLVD., 12TH FLOOR WOODLAND HILLS CA 91367 1 1 Founder 0 Common Stock 2026-02-20 4 M 0 21761 36.15 A 372889 D Common Stock 2026-02-20 4 M 0 9332 36.15 A 382221 D Common Stock 2026-02-20 4 M 0 11225 36.15 A 393446 D Common Stock 2026-02-20 4 F 0 31786 36.15 D 361660 D Common Stock 100178 I Brian and Therese Tucker Charitable Remainder Trust Common Stock 1509881 I Brian and Therese Tucker Living Trust Common Stock 54074 I Claire Seimetz 2015 Trust Common Stock 577200 I Isaac Tucker 2012 Irrevocable Trust Common Stock 577200 I Roseanna Tucker 2012 Irrevocable Trust Common Stock 52444 I Tucker Family CLAT Common Stock 874128 I Tucker Legacy Trust Common Stock 129897 I Tucker Legacy Trust II Common Stock 250916 I Tucker Seimetz Safety Net Grat The reported shares relate to the portion of a Performance Based Restricted Stock Unit ("PRSU") granted on March 7, 2023 that has vested based on the Issuer's achievement of certain fiscal 2023 performance targets that were set by the Compensation Committee at the time of grant. The reported shares relate to the portion of a PRSU granted on March 17, 2024 that has vested based on the Issuer's achievement of certain fiscal 2024 performance targets that were set by the Compensation Committee at the time of grant. The reported shares relate to the portion of a PRSU granted on April 2, 2025 that has vested based on the Issuer's achievement of certain fiscal 2025 performance targets that were set by the Compensation Committee at the time of grant. The reported shares were withheld to cover the reporting person's tax liability in connection with the vesting of PRSUs and restricted stock units. /s/ Karole Morgan-Prager, Attorney-in-Fact 2026-02-24