Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Stock^{F1,F2,F3,F7,F8}	Mar 15, 2018	S	1,241,911	$40.75	D	2,919,220	D
Common Stock^{F1,F2,F4,F7,F8}	Mar 15, 2018	S	311,694	$40.75	D	732,666	D
Common Stock^{F1,F2,F5,F7,F8}	Mar 15, 2018	S	390,108	$40.75	D	916,983	D
Common Stock^{F1,F2,F6,F7,F8}	Mar 15, 2018	S	56,287	$40.75	D	132,307	D
Common Stock^F9	holding	—	—		—	4,701,176	I	See Footnote
Common Stock^F10	holding	—	—		—	17,087	D

Table II — derivative securities

No Table II lines on this filing.

Explanation of responses

F1Represents shares of BlackLine, Inc.'s (the "Issuer") Common Stock sold in an underwritten secondary offering.
F10These shares are directly held by Makan through a family trust that he controls.
F2Represents the sale price to the underwriters in the secondary offering of $40.75 per share.
F3ICONIQ Strategic Partners, L.P. ("ICONIQ") is the direct owner of these securities.
F4ICONIQ Strategic Partners-B, L.P. ("ICONIQ B") is the direct owner of these securities.
F5ICONIQ Strategic Partners Co-Invest, L.P., BL Series ("ICONIQ BL") is the direct owner of these securities.
F6ICONIQ Strategic Partners Co-Invest, L.P., BL2 Series ("ICONIQ BL2") is the direct owner of these securities.
F7Iconiq Strategic Partners GP, L.P. ("ICONIQ GP") is the sole general partner of each of ICONIQ, ICONIQ B, ICONIQ BL and ICONIQ BL2 (collectively, the "Funds"). ICONIQ Strategic Partners TT GP, Ltd. (the "ICONIQ Parent GP") is the sole general partner of ICONIQ GP. Divesh Makan ("Makan") is an equity holder and director of ICONIQ Parent GP.
F8Each of ICONIQ GP, ICONIQ Parent GP and Makan disclaims beneficial ownership of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its or his pecuniary interest therein, if any. This report shall not be deemed an admission that any of the Reporting Persons is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.
F9This number represents shares held by ICONIQ (2,919,220), ICONIQ B (732,666), ICONIQ BL (916,983), and ICONIQ BL2 (132,307), respectively. Each of ICONIQ GP, ICONIQ Parent GP and Makan disclaims beneficial ownership of the securities reported herein for purposes of Section 16 of the Exchange Act, except to the extent of its or his pecuniary interest therein, if any. This report shall not be deemed an admission that any of the Reporting Persons is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.