X0508 4 2024-12-12 0001666134 BLACKLINE, INC. BL 0001838158 Woodhams Mark 21300 VICTORY BLVD., 12TH FLOOR WOODLAND HILLS CA 91367 1 Chief Revenue Officer 1 Common Stock 2024-12-12 4 M 0 7998 49.04 A 93784 D Common Stock 2024-12-12 4 M 0 3544 48.65 A 97328 D Common Stock 2024-12-12 4 S 0 21242 64.25 D 76086 D Common Stock 2024-12-12 4 S 0 3166 64.78 D 72920 D Stock Option (Right to Buy) 48.65 2024-12-12 4 M 0 3544 0 D 2029-05-15 Common Stock 3544 30356 D Stock Option (Right to Buy) 49.04 2024-12-12 4 M 0 7998 0 D 2028-08-07 Common Stock 7998 81095 D The transaction reported on this Form 4 was effectuated pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 13, 2024. The sale price represents the weighted average price of shares sold ranging from $63.74 to $64.73 per share, and is rounded to the nearest tenth of a cent. Upon request by the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, the reporting person will provide full information regarding the number of shares sold at each separate price within the range set forth in this Form 4. The sale price represents the weighted average price of shares sold ranging from $64.74 to $64.86 per share, and is rounded to the nearest tenth of a cent. Upon request by the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, the reporting person will provide full information regarding the number of shares sold at each separate price within the range set forth in this Form 4. The options became exercisable based on the following vesting schedule, which shall be satisfied over a 5-year period: 25% of the shares subject to the option vested on the one (1) year anniversary of the grant date (the "Annual Option Vesting Commencement Date"), and 1/16th of the remaining options vest every three months thereafter on the same day of the month as the Annual Option Vesting Commencement Date, subject to the reporting person's continued service through each applicable vesting date. /s/ Karole Morgan-Prager, Attorney-in-Fact 2024-12-16