Sec Form 4 Filing - Hinds Brent @ ClearSign Technologies Corp - 2025-02-24

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 Hinds Brent 2. Issuer Name and Ticker or Trading Symbol ClearSign Technologies Corp [ CLIR] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Financial Officer (Last) (First) (Middle) 8023 E. 63RD PLACE, SUITE 101 3. Date of Earliest Transaction (MM/DD/YY) 02/24/2025 (Street) TULSA, OK74133 4. If Amendment, Date Original Filed (MM/DD/YY) 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 (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 02/24/2025 M 7,547 ( 1 ) A 120,476 D Common Stock 02/24/2025 F 2,636 ( 2 ) D $ 0.7994 117,840 D

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 Restricted Stock Unit ( 3 ) 02/24/2025 M 7,547 ( 4 ) ( 4 ) Common Stock 7,547 $ 0 15,094 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Hinds Brent 8023 E. 63RD PLACE, SUITE 101 TULSA, OK74133 Chief Financial Officer Signatures /s/ Brent Hinds 02/25/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Reflects the vesting of 7,547 restricted stock units ("RSUs") out of the 22,641 RSUs granted to the reporting person on February 22, 2024, into an equal number of shares of the Company's common stock, without the payment of any consideration, pursuant to the Company's 2021 Equity Incentive Plan. ( 2 )Represents the payment of the reporting person's tax liability by withholding shares in connection with the vesting of 7,547 RSUs on February 24, 2025, and calculated based on the closing price of the Company's common stock, as reported on Nasdaq Stock Market, on February 24, 2025, of $0.7994. ( 3 )On February 22, 2024, the reporting person was granted a one-time bonus of 22,641 RSUs, and each RSU represents a right to receive one share of common stock or the cash equivalent thereof. ( 4 )The RSUs granted on February 22, 2024, vest in three equal annual installments that commenced on February 24, 2025.

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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