12. Stockholders’ equity

Shares issued

During the three months ended March 31, 2025, the Company issued 58,349 shares of common stock upon vesting of Restricted Stock Units ("RSUs") granted by the Company to management and employees, including 29,419 of reissued treasury stock. We withheld 26,476 shares to satisfy approximately $67,000 of employees’ tax obligations during the three months ended March 31, 2025. We treat shares of common stock withheld for tax purposes on behalf of our employees in connection with the vesting of RSUs in a similar manner as common stock repurchases and reported as treasury stock. 

During the three months ended March 31, 2025, the Company issued 3,353 shares of common stock upon vesting of RSUs granted to Board members.

During the three months ended March 31, 2025, the Company issued 596,487 shares of common stock pursuant to the at the market issuance sales agreement for net proceeds of $1,214,000.

During the three months ended March 31, 2024, the Company issued 52,804 shares of common stock upon vesting of Restricted Stock Units ("RSUs") granted by the Company to management and employees, including 21,428 of reissued treasury stock. We withheld 22,832 shares to satisfy approximately $360,000 of employees’ tax obligations during the three months ended March 31, 2024. We treat shares of common stock withheld for tax purposes on behalf of our employees in connection with the vesting of RSUs in a similar manner as common stock repurchases and reported as treasury stock. 

During the three months ended March 31, 2024, the Company issued 1,988 shares of common stock upon vesting of RSUs granted to Board members. 

During the three months ended March 31, 2024, the Company issued 207,781 shares of common stock pursuant to the at the market issuance sales agreement for net proceeds of $2,126,000. 

Stock-based compensation

The stock-based compensation expense was allocated as follows:

2019 Stock Incentive Plan

In 2019, our board of directors adopted the Aqua Metals, Inc. 2019 Stock Incentive Plan (the “2019 Plan”). On May 23, 2024, 475,000 shares of common stock were authorized and added to the plan. As of March 31, 2025, a total of 1,400,000 shares of common stock was authorized for issuance pursuant to the 2019 Plan. The 2019 Plan provides for the following types of stock-based awards: incentive stock options; non-statutory stock options; restricted stock; restricted stock units, or RSUs; and performance stock units, or PSUs. The 2019 Plan, under which options  may be granted to employees and directors under incentive and non-statutory agreements, requires that the option price may not be less than the fair value of the stock at the date the option is granted. Option awards are exercisable until their expiration, which may not exceed 10 years from the grant date. 

As of March 31, 2025, the Company has granted RSUs and PSUs under the 2019 Plan, which upon settlement entitle their holders to receive 1,164,504 shares of common stock, all of which are subject to future vesting conditions, which exceeds the 786,611 shares available for issuance. The Company has established a sequencing policy such that grants with the latest grant date will be reclassified to liabilities first. Considering this policy and the terms of the underlying grants, this Company has reclassified 377,893 of its service-based RSUs to liabilities as of  March 31, 2025.

Restricted stock units

During the first quarter of 2025, the Company granted 5,347 RSUs to an employee, all of which were subject to vesting, with a grant date fair value of $10,000. The shares vest in three equal installments over a three-year period.

On  October 3, 2024, the Company approved a supplemental retention program designed to retain business-critical resources essential to ongoing operations and strategic initiatives. Participation in the program is contingent upon management achieving specified fundraising targets and subject to the continued service of eligible employees. The program established specific funding tranches tied to cumulative fundraising milestones, which must be achieved on or before  March 7, 2025. The grant terms included a fixed dollar, variable share, structure with potential settlement valued from $0 to $925,014 dependent upon satisfaction of performance conditions. Once performance conditions are met, the shares to be granted are fixed and subject to an additional six-month service condition. During the first quarter of 2025, the first funding tranche was achieved, triggering the issuance of 118,469 RSUs to qualified employees in accordance with the program’s terms. These shares have been granted subject to continued service requirements.

During the first quarter of 2025, the Company granted 25,000 RSUs to an employee, all of which were subject to vesting, with a grant date fair value of $49,000. The shares vest over a six-month period.