Meyers Brad Ian

SEC source: 0001654954-26-005991 · form4.xml · nonDerivative · entry 2

Meyers Brad Ian · CIK 0002000149 · Chief Operating Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,169

F2 · price: The Reporting Person sold all 9,831 shares of common stock in the open market at a price of $2.33 per share.

SEC source: 0001654954-26-005991 · form4.xml · nonDerivative · entry 1

Meyers Brad Ian · CIK 0002000149 · Chief Operating Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 40,000

F1 · price: The Reporting Person sold all 9,000 shares of common stock in the open market at a price of $2.46 per share.

SEC source: 0001654954-25-011764 · section16.xml · derivative · entry 1

Meyers Brad Ian · CIK 0002000149 · Chief Operating Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 731,000

Underlying: Common Stock · 500,000 shares

Expires not disclosed

F1 · security: Represents stock options granted to the Reporting Person as a special retention incentive award in connection with his continued service as Chief Operating Officer of 374Water Inc. (the "Company"). 50% of the stock options vest and become exercisable on the first anniversary of the grant date and the remaining 50% of the stock options vest and become exercisable on the second anniversary of the grant date, subject to the Reporting Person's continuous service through each vesting date. In the event of an involuntary termination of the Reporting Person without cause, all remaining unvested stock options will vest and become exercisable immediately. Upon vesting, each stock option gives the Reporting Person the right to purchase one share of the Company's Common Stock at the exercise price. The stock options expire on the date which is ten years from the grant date, unless earlier terminated in accordance with the stock option grant agreement.

F1 · shares: Represents stock options granted to the Reporting Person as a special retention incentive award in connection with his continued service as Chief Operating Officer of 374Water Inc. (the "Company"). 50% of the stock options vest and become exercisable on the first anniversary of the grant date and the remaining 50% of the stock options vest and become exercisable on the second anniversary of the grant date, subject to the Reporting Person's continuous service through each vesting date. In the event of an involuntary termination of the Reporting Person without cause, all remaining unvested stock options will vest and become exercisable immediately. Upon vesting, each stock option gives the Reporting Person the right to purchase one share of the Company's Common Stock at the exercise price. The stock options expire on the date which is ten years from the grant date, unless earlier terminated in accordance with the stock option grant agreement.

F1 · derivative.exercise_date: Represents stock options granted to the Reporting Person as a special retention incentive award in connection with his continued service as Chief Operating Officer of 374Water Inc. (the "Company"). 50% of the stock options vest and become exercisable on the first anniversary of the grant date and the remaining 50% of the stock options vest and become exercisable on the second anniversary of the grant date, subject to the Reporting Person's continuous service through each vesting date. In the event of an involuntary termination of the Reporting Person without cause, all remaining unvested stock options will vest and become exercisable immediately. Upon vesting, each stock option gives the Reporting Person the right to purchase one share of the Company's Common Stock at the exercise price. The stock options expire on the date which is ten years from the grant date, unless earlier terminated in accordance with the stock option grant agreement.

F1 · derivative.expiration_date: Represents stock options granted to the Reporting Person as a special retention incentive award in connection with his continued service as Chief Operating Officer of 374Water Inc. (the "Company"). 50% of the stock options vest and become exercisable on the first anniversary of the grant date and the remaining 50% of the stock options vest and become exercisable on the second anniversary of the grant date, subject to the Reporting Person's continuous service through each vesting date. In the event of an involuntary termination of the Reporting Person without cause, all remaining unvested stock options will vest and become exercisable immediately. Upon vesting, each stock option gives the Reporting Person the right to purchase one share of the Company's Common Stock at the exercise price. The stock options expire on the date which is ten years from the grant date, unless earlier terminated in accordance with the stock option grant agreement.

F1 · derivative.underlying_shares: Represents stock options granted to the Reporting Person as a special retention incentive award in connection with his continued service as Chief Operating Officer of 374Water Inc. (the "Company"). 50% of the stock options vest and become exercisable on the first anniversary of the grant date and the remaining 50% of the stock options vest and become exercisable on the second anniversary of the grant date, subject to the Reporting Person's continuous service through each vesting date. In the event of an involuntary termination of the Reporting Person without cause, all remaining unvested stock options will vest and become exercisable immediately. Upon vesting, each stock option gives the Reporting Person the right to purchase one share of the Company's Common Stock at the exercise price. The stock options expire on the date which is ten years from the grant date, unless earlier terminated in accordance with the stock option grant agreement.

SEC source: 0001654954-25-010348 · section16.xml · nonDerivative · entry 1

Meyers Brad Ian · CIK 0002000149 · Chief Operating Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 490,000

SEC source: 0001654954-25-010347 · section16.xml · derivative · entry 2

Meyers Brad Ian · CIK 0002000149 · Chief Operating Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 115,500

Underlying: Common Stock, $0.0001 par value · 115,500 shares

Expires not disclosed

F1 · shares: The Restricted Stock Units (the "RSU") reported herein were granted to the Reporting Person May 16, 2024 (the "Effective Date") pursuant to his Employment Agreement (the "Employment Agreement"). The RSU grants consisted of an RSU for 115,500 shares that vest over time (the "Time RSU") and an RSU for 115,500 shares that vest on the achievement of certain milestones (the "Performance RSU"). 28,875 of the shares subject to the Time RSU vested on May 16, 2025, and the remaining 86,625 shares vest in equal increments on the last day of every month thereafter over the following 36 months, subject to the Reporting Person's continued employment with the Issuer on each vesting date. As of September 2, 2025, 36,093 shares subject to the Time RSU were vested, and 79,407 shares are unvested.

F3 · derivative.exercise_date: Under the Employment Agreement, the Reporting Person was granted the Performance RSU, that vest pursuant to certain milestones set forth by the Issuer.

F3 · derivative.expiration_date: Under the Employment Agreement, the Reporting Person was granted the Performance RSU, that vest pursuant to certain milestones set forth by the Issuer.

F2 · balance_after: On May 22, 2024, the Reporting Person filed a Form 4 that reported both the Time RSU and the Performance RSU in Table II. This amendment serves to remove the Time RSU from Table II and report it in Table I.

SEC source: 0001654954-25-010347 · section16.xml · nonDerivative · entry 1

Meyers Brad Ian · CIK 0002000149 · Chief Operating Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 115,500

F1 · shares: The Restricted Stock Units (the "RSU") reported herein were granted to the Reporting Person May 16, 2024 (the "Effective Date") pursuant to his Employment Agreement (the "Employment Agreement"). The RSU grants consisted of an RSU for 115,500 shares that vest over time (the "Time RSU") and an RSU for 115,500 shares that vest on the achievement of certain milestones (the "Performance RSU"). 28,875 of the shares subject to the Time RSU vested on May 16, 2025, and the remaining 86,625 shares vest in equal increments on the last day of every month thereafter over the following 36 months, subject to the Reporting Person's continued employment with the Issuer on each vesting date. As of September 2, 2025, 36,093 shares subject to the Time RSU were vested, and 79,407 shares are unvested.

SEC source: 0001654954-24-006781 · section16.xml · derivative · entry 2

Meyers Brad Ian · CIK 0002000149 · Chief Operating Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 231,000

Underlying: Common Stock, $0.001 par value · 231,000 shares

Expires 2034-05-16

F1 · security: The Restricted Stock Units (the "RSUs") and Option to Purchase Common Stock (the "Options) reported herein were granted to the Reporting Person on May 16, 2024 (the "Effective Date") pursuant to his Employment Agreement (the "Employment Agreement").

F3 · derivative.exercise_date: Under the Employment Agreement and subject to the terms of the Plan, the Reporting Person was granted up to 231,000 Options under the Plan, vesting as follows: (a) with respect to 115,500 Options, 25% shall vest on the first anniversary of the Effective Date, and the remaining 75% shall vest in equal increments over the following 36 months; and (b) with respect to the remaining 115,500 Options, each shall vest in accordance with the Company milestones set forth by the Issuer.

SEC source: 0001654954-24-006781 · section16.xml · derivative · entry 1

Meyers Brad Ian · CIK 0002000149 · Chief Operating Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 231,000

Underlying: Common Stock, $0.001 par value · 231,000 shares

Expires not disclosed

F1 · security: The Restricted Stock Units (the "RSUs") and Option to Purchase Common Stock (the "Options) reported herein were granted to the Reporting Person on May 16, 2024 (the "Effective Date") pursuant to his Employment Agreement (the "Employment Agreement").

F2 · derivative.exercise_date: Under the Employment Agreement and subject to the terms of the Issuer's 2021 Equity Incentive Plan (the "Plan"), the Reporting Person was granted up to 231,000 RSUs under the Plan, vesting as follows: (a) with respect to 115,500 RSUs, 25% shall vest on the first anniversary of the Effective Date (as defined in the Employment Agreement), and the remaining 75% shall vest in equal increments over the following 36 months; and (b) with respect to the remaining 115,500 RSUs, each shall vest in accordance with the Company milestones set forth by the Issuer.

F2 · derivative.expiration_date: Under the Employment Agreement and subject to the terms of the Issuer's 2021 Equity Incentive Plan (the "Plan"), the Reporting Person was granted up to 231,000 RSUs under the Plan, vesting as follows: (a) with respect to 115,500 RSUs, 25% shall vest on the first anniversary of the Effective Date (as defined in the Employment Agreement), and the remaining 75% shall vest in equal increments over the following 36 months; and (b) with respect to the remaining 115,500 RSUs, each shall vest in accordance with the Company milestones set forth by the Issuer.