# EDGAR Filing Document

**Accession Number:** 0001434524
**File Stem:** 0001104659-26-019278
**Filing Date:** 2026-2
**Character Count:** 8195
**Document Hash:** 408b5102d8fd75730769d504aefd0a42
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-26-019278.hdr.sgml**: 20260224

**ACCESSION NUMBER**: 0001104659-26-019278

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260220

**FILED AS OF DATE**: 20260224

**DATE AS OF CHANGE**: 20260224

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Hinds Brent
- **CENTRAL INDEX KEY:** 0001888082

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-35521
- **FILM NUMBER:** 26673581

**MAIL ADDRESS:**
- **STREET 1:** 12870 INTERURBAN AVENUE SOUTH
- **CITY:** SEATTLE
- **STATE:** WA
- **ZIP:** 98168
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** ClearSign Technologies Corp
- **CENTRAL INDEX KEY:** 0001434524
- **STANDARD INDUSTRIAL CLASSIFICATION:** INDUSTRIAL INSTRUMENTS FOR MEASUREMENT, DISPLAY, AND CONTROL [3823]
- **ORGANIZATION NAME:** 08 Industrial Applications and Services
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 8023 E. 63RD PLACE, SUITE 101
- **CITY:** TULSA
- **STATE:** OK
- **ZIP:** 74133
- **BUSINESS PHONE:** (918) 500-7312

**MAIL ADDRESS:**
- **STREET 1:** 8023 E. 63RD PLACE, SUITE 101
- **CITY:** TULSA
- **STATE:** OK
- **ZIP:** 74133

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** CLEARSIGN COMBUSTION CORP
- **DATE OF NAME CHANGE:** 20080507

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] 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 for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Hinds Brent<br><sub>(Last) (First) (Middle)</sub><br>8023 E. 63RD PLACE, SUITE 101<br><sub>(Street)</sub><br>TULSA, OK 74133<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-02-20 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [ ] 10% Owner<br>[X] Officer (give title below) [ ] Other (specify below)<br>_Chief Financial Officer_ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>ClearSign Technologies Corp [ CLIR ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2026-02-20 |  | M |  | 9315<sup>(1)</sup> | A | <sup>(1)</sup> | 133571 | D |  |
| Common Stock | 2026-02-20 |  | F |  | 3413<sup>(2)</sup> | D | $0.5949 | 130158 | D |  |
| Common Stock | 2026-02-22 |  | M |  | 7547<sup>(3)</sup> | A | <sup>(3)</sup> | 137705 | D |  |
| Common Stock | 2026-02-22 |  | F |  | 2765<sup>(4)</sup> | D | $0.5949 | 134940 | D |  |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Restricted Stock Unit | <sup>(5)</sup> | 2026-02-20 |  | M |  |  | 9315 | <sup>(6)</sup> | <sup>(6)</sup> | Common Stock | 9315 | $0 | 18631 | D |  |
| Restricted Stock Unit | <sup>(7)</sup> | 2026-02-22 |  | M |  |  | 7547 | <sup>(8)</sup> | <sup>(8)</sup> | Common Stock | 7547 | $0 | 7547 | D |  |

---

### Footnotes:

(1) Reflects the vesting of 9,315 restricted stock units ("RSUs") out of the 27,946 RSUs granted to the reporting person on February 20, 2025, 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 9,315 RSUs on February 20, 2026, and calculated based on the closing price of the Company's common stock, as reported on the Nasdaq Stock Market, on February 20, 2026, of $0.5949.

(3) Reflects the vesting of 7,547 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.

(4) Represents the payment of the reporting person's tax liability by withholding shares in connection with the vesting of 7,547 RSUs on February 22, 2026, and calculated based on the closing price of the Company's common stock, as reported on the Nasdaq Stock Market, on February 20, 2026, of $0.5949 (as February 22, 2026 fell on a weekend).

(5) On February 20, 2025, the reporting person was granted 27,946 RSUs as a one-time bonus for services as an executive officer for the year ended December 31, 2024, and each RSU represents a right to receive one share of common stock or the cash equivalent thereof.

(6) The RSUs granted on February 20, 2025, vest in three equal installments that commenced on February 20, 2026.

(7) On February 22, 2024, the reporting person was granted 22,641 RSUs as a one-time bonus for services as an executive officer for the year ended December 31, 2023, and each RSU represents a right to receive one share of common stock or the cash equivalent thereof.

(8) The RSUs granted on February 22, 2024, vest in three equal installments that commenced on February 22, 2025.

**Signature:** /s/ Brent Hinds  
**Date:** 2026-02-24

### Remarks:

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).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**