Sec Form 4 Filing - ICONIQ Strategic Partners, L.P. @ BLACKLINE, INC. - 2020-02-28

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person ICONIQ Strategic Partners, L.P. 2. Issuer Name and Ticker or Trading Symbol BLACKLINE, INC. [ BL] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O ICONIQ STRATEGIC PARTNERS, 394 PACIFIC AVENUE, 2ND FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 02/28/2020 (Street) SAN FRANCISCO, CA94111 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 02/28/2020 S 63 D 623 D ( 1 ) ( 3 ) ( 4 ) Common Stock 02/28/2020 S 26 D 263 D ( 2 ) ( 3 ) ( 4 ) Common Stock 02/28/2020 S 259 D 364 D ( 1 ) ( 3 ) ( 4 ) Common Stock 02/28/2020 S 109 D 154 D ( 2 ) ( 3 ) ( 4 ) Common Stock 02/28/2020 S 148 D 216 D ( 1 ) ( 3 ) ( 4 ) Common Stock 02/28/2020 S 63 D 91 D ( 2 ) ( 3 ) ( 4 ) Common Stock 02/28/2020 S 214 D 2 D ( 1 ) ( 3 ) ( 4 ) Common Stock 02/28/2020 S 90 D 1 D ( 2 ) ( 3 ) ( 4 ) Common Stock 02/28/2020 S 2 D 0 D ( 1 ) ( 3 ) ( 4 ) Common Stock 02/28/2020 S 1 D 0 D ( 2 ) ( 3 ) ( 4 ) Common Stock 0 I ( 5 ) See Footnote ( 5 ) Common Stock 297,702 D ( 6 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other ICONIQ Strategic Partners, L.P. C/O ICONIQ STRATEGIC PARTNERS 394 PACIFIC AVENUE, 2ND FLOOR SAN FRANCISCO, CA94111 X ICONIQ Strategic Partners Co-Invest, L.P., BL Series C/O ICONIQ STRATEGIC PARTNERS 394 PACIFIC AVENUE, 2ND FLOOR SAN FRANCISCO, CA94111 X ICONIQ Strategic Partners Co-Invest, L.P., Series BL2 C/O ICONIQ STRATEGIC PARTNERS 394 PACIFIC AVENUE, 2ND FLOOR SAN FRANCISCO, CA94111 X ICONIQ Strategic Partners GP, L.P. C/O ICONIQ STRATEGIC PARTNERS 394 PACIFIC AVENUE, 2ND FLOOR SAN FRANCISCO, CA94111 X ICONIQ Strategic Partners TT GP, Ltd. C/O ICONIQ STRATEGIC PARTNERS 394 PACIFIC AVENUE, 2ND FLOOR SAN FRANCISCO, CA94111 X Makan Divesh C/O ICONIQ STRATEGIC PARTNERS 394 PACIFIC AVENUE, 2ND FLOOR SAN FRANCISCO, CA94111 X Signatures ICONIQ Strategic Partners Co-Invest, L.P., BL Series, by ICONIQ Strategic Partners GP, L.P., its general partner, by ICONIQ Strategic Partners TT GP, Ltd., its general partner, by Kevin Foster, its Senior Vice President, /s/ Kevin Foster 03/03/2020 Signature of Reporting Person Date ICONIQ Strategic Partners Co-Invest, L.P., BL2 Series, by ICONIQ Strategic Partners GP, L.P., its general partner, by ICONIQ Strategic Partners TT GP, Ltd., its general partner, by Kevin Foster, its Senior Vice President, /s/ Kevin Foster 03/03/2020 Signature of Reporting Person Date ICONIQ Strategic Partners GP, L.P., by ICONIQ Strategic Partners TT GP, Ltd., its general partner, by Kevin Foster, its Senior Vice President, /s/ Kevin Foster 03/03/2020 Signature of Reporting Person Date ICONIQ Strategic Partners TT GP, Ltd., by Kevin Foster, its Senior Vice President, /s/ Kevin Foster 03/03/2020 Signature of Reporting Person Date /s/ Divesh Makan 03/03/2020 Signature of Reporting Person Date

Explanation of Responses:

( 1 )ICONIQ Strategic Partners Co-Invest, L.P., BL Series ("ICONIQ BL Series") is the direct owner of these securities. ( 2 )ICONIQ Strategic Partners Co-Invest, L.P., BL2 Series ("ICONIQ BL2 Series") is the direct owner of these securities. ( 3 )Iconiq Strategic Partners GP, L.P. ("ICONIQ GP") is the sole general partner of each of ICONIQ BL Series and ICONIQ BL2 Series (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. ( 4 )Each 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. ( 5 )This number represents shares held by ICONIQ Strategic Partners, L.P. (0), ICONIQ Strategic Partners-B, L.P. (0), ICONIQ BL Series (0), and ICONIQ BL2 Series (0) 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. ( 6 )These shares are directly held by Makan through a family trust that he controls. ( 7 )These shares were sold in multiple transactions at prices ranging from $59.86 - $60.85, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. ( 8 )These shares were sold in multiple transactions at prices ranging from $60.86 - $61.85, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. ( 9 )These shares were sold in multiple transactions at prices ranging from $61.86 - $62.85, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. ( 10 )These shares were sold in multiple transactions at prices ranging from $62.86 - $63.85, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. ( 11 )These shares were sold in multiple transactions at prices ranging from $63.85 - $63.92, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

Remarks: The Funds are party to a Stockholders' Agreement, dated as of October 27, 2016 (the "Stockholders' Agreement"), by and among entities affiliated with each of Therese Tucker and Mario Spanicciati (collectively, the "Other Stockholders") and the Company. By virtue of being a party to the Stockholders' Agreement, each of the Funds may be deemed to be members of a "group", as defined in Rule 13d-5 of the Exchange Act, with the Other Stockholders and/or certain of their affiliates. This report does not include any shares of the Common Stock owned by the Other Stockholders, and each of the Funds and the other reporting persons on this report disclaims beneficial ownership of all such shares for all purposes. The Stockholders' Agreement is now of no application to the Reporting Person and its affiliates given that none of the Funds own any shares.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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