12. Employee Benefit Plans

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2011 and 2021 Stock Option and Incentive Plan

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Stock-based compensation costs recognized, excluding the Company’s matching contributions of $2.9 million and $2.8 million to the Plug Power Inc. 401(k) Savings & Retirement Plan and quarterly Board and executive compensation, were $11.2 million and $8.5 million for the three months ended March 31, 2026 and 2025, respectively. The methods and assumptions used in the determination of the fair value of stock-based awards are consistent with those described in our 2025 Form 10-K.

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The components and classification of stock-based compensation expense, excluding the Company’s matching contributions to the Plug Power Inc. 401(k) Savings & Retirement Plan and quarterly Board compensation, were as follows (in thousands):

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Service Stock Options Awards

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During the three months ended March 31, 2026, the Company granted 295,898 service stock option awards at a weighted average exercise price of $1.54. In addition, 43,584 service stock option awards were exercised at a weighted average exercise price of $2.07. Finally, 1,020,288 service stock option awards were forfeited at a weighted average exercise price of $9.41. The total fair value of the service stock option awards that vested during the three months ended March 31, 2026 and 2025 was approximately $0.3 million and $1.9 million, respectively.

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Compensation cost associated with service stock option awards represented approximately $6.6 million and $3.5 million of the total share-based payment expense recorded during the three months ended March 31, 2026 and 2025, respectively. As of March 31, 2026, there was approximately $44.9 million of unrecognized compensation cost related to service stock option awards to be recognized over the weighted average remaining period of 2.13 years.

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Market Condition Stock Option Awards

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During the three months ended March 31, 2026, the Company did not grant market condition stock option awards. In addition, no market condition stock option awards were exercised or forfeited during the three months ended March 31, 2026.

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Compensation cost associated with market condition stock option awards represented approximately $0.6 million and $0.3 million of the total share-based payment expense recorded during the three months ended March 31, 2026 and 2025, respectively. Compensation costs associated with these awards are recognized as the requisite service period is rendered, regardless of when, if ever, the market condition is satisfied. As of March 31, 2026, there was approximately $0.3 million of unrecognized compensation cost related to market condition stock option awards to be recognized over the weighted average remaining period of 0.29 years.

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As of March 31, 2026, there were 1,045,000 unvested market condition stock option awards for which the employee requisite service period had not been rendered but were expected to vest. The aggregate intrinsic value of these unvested market condition stock option awards was $0 as of March 31, 2026. As of March 31, 2026, the weighted average exercise price of these unvested market condition stock option awards was $7.87 and the weighted average remaining contractual term was 4.13 years.

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Restricted Stock and Restricted Stock Unit Awards

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During the three months ended March 31, 2026, the Company granted 45,000 restricted stock awards at a weighted average exercise price of $1.79. In addition, 166,831 restricted stock and restricted stock unit awards were forfeited at a weighted average exercise price of $4.63. The total fair value of the 17,833 restricted stock and restricted stock unit awards that vested during the three months ended March 31, 2026 and 2025 was approximately $0.1 million and $1.7 million, respectively.

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Compensation cost associated with restricted stock and restricted stock unit awards represented approximately $4.0 million and $4.7 million during the three months ended March 31, 2026 and 2025, respectively. As of March 31, 2026, there was $21.7 million of unrecognized compensation cost related to restricted stock and restricted stock unit awards to be recognized over the weighted average period of 2.15 years.

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401(k) Savings & Retirement Plan

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The Company issued 1,340,602 and 1,460,079 shares of common stock pursuant to the Plug Power Inc. 401(k) Savings & Retirement Plan during the three months ended March 31, 2026 and 2025, respectively.

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The Company’s expense for this plan was approximately $2.9 million and $2.8 million during the three months ended March 31, 2026 and 2025, respectively.

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Non-Employee Director Compensation

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The Company granted 45,585 and 134,491 shares of common stock to non-employee directors as compensation during the three months ended March 31, 2026 and 2025, respectively. All common stock issued is fully vested at the time of issuance and is valued at fair value on the date of issuance. The Company’s share-based compensation expense in connection with non-employee director compensation was approximately $0.1 million and $0.2 million during the three months ended March 31, 2026 and 2025, respectively.

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During the three months ended March 31, 2026, non-employee directors were also granted 163,638 service stock option awards and 87,260 common stock options that vest over a one and three year period, respectively, with the 163,638 service stock option awards included within the total 295,898 service stock option awards disclosed above. The Company’s share-based compensation expense in connection with these awards was approximately $19 thousand during the three months ended March 31, 2026. Additionally, in accordance with the non-employee director compensation plan, during the

three months ended March 31, 2026 and 2025, the Company reimbursed $0 and $0.1 million of administrative expenses incurred by non-employee directors, respectively.