Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

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

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1. Name and Address of Reporting Person * Tucker Therese 2. Issuer Name and Ticker or Trading Symbol BLACKLINE, INC. [BL] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 21300 VICTORY BLVD., 12TH FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 08/24/2026 (Street) WOODLAND HILLS, CA 91367 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ 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 (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 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 08/24/2026 M 70,000 A $14 424,997 D Common Stock 08/24/2026 M 26,560 A $14 451,557 D Common Stock 08/24/2026 S 70,000 D $31.957(1) 381,557 D Common Stock 100,178 I Brian and Therese Tucker Charitable Remainder Trust Common Stock 1,509,881 I Brian and Therese Tucker Living Trust Common Stock 54,074 I Claire Seimetz 2015 Trust Common Stock 577,200 I Isaac Tucker 2012 Irrevocable Trust Common Stock 577,200 I Roseanna Tucker 2012 Irrevocable Trust Common Stock 52,444 I Tucker Family CLAT Common Stock 874,128 I Tucker Legacy Trust Common Stock 129,897 I Tucker Legacy Trust II Common Stock 250,916 I Tucker Seimetz Safety Net Grat

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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 (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

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 (Month/Day/Year)

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

Stock Option (Right to Buy)

$14

08/24/2026

M

70,000

(2)

10/16/2026

Common Stock

70,000

$ 0

26,560

D

Stock Option (Right to Buy)

$14

08/24/2026

M

26,560

(2)

10/16/2026

Common Stock

26,560

$ 0

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Tucker Therese 21300 VICTORY BLVD., 12TH FLOOR WOODLAND HILLS, CA 91367	X

Signatures

/s/ Karole Morgan-Prager, Attorney-in-Fact		08/26/2026
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	The sale price represents the weighted-average price of shares sold ranging from $31.78 to $32.14 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.
(2)	The options became exercisable based on the following vesting schedule: The shares subject to the option vested in 4 equal, annual installments beginning on the one-year anniversary of the grant date, subject to the reporting person's continued service through each applicable vesting date.

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