X0306 4 2017-11-15 0 0001666134 BLACKLINE, INC. BL 0001688365 Tucker Therese 21300 VICTORY BLVD., 12TH FLOOR WOODLAND HILLS CA 91367 1 1 0 0 Chief Executive Officer Common Stock 2017-11-15 4 S 0 2000 35.31 D 375303 I SAFETY NET GRAT dated 9/28/2015 Common Stock 3424945 D Common Stock 1200000 I Tucker Legacy Trust Common Stock 637200 I Isaac Tucker 2012 Irrevocable Trust Common Stock 637200 I Roseanna Tucker 2012 Irrevocable Trust Common Stock 75352 I CS 2015 GRAT dated 9/28/2015 The sale transaction reported on this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adapted by the Reporting Person on September 13, 2017. The sale price represents the weighted average price of the shares sold ranging from $35.04 to $35.40 per share. Upon request by the 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. Totals reflect scheduled distributions of common stock to Ms. Tucker from the Safety Net GRAT dated 9/28/2015 and the CS 2015 GRAT dated 9/28/2015. /s/ Karole Morgan-Prager, Attorney-in-Fact 2017-11-16