Stock-Based Compensation

3 Months Ended

Mar. 31, 2026

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

4. STOCK-BASED COMPENSATION

2024 Stock Incentive Plans

At the annual meeting of stockholders held on May 8, 2024, the Company’s stockholders approved, upon recommendation of the Board of Directors, the adoption of the ADTRAN Holdings, Inc. 2024 Employee Stock Incentive Plan (“2024 Employee Plan”) and the ADTRAN Holdings, Inc. 2024 Directors Stock Plan (“2024 Directors Plan”). Outstanding awards granted under the Company's prior equity incentive plans will remain subject to the terms of such applicable plans, and shares under such plans that are cancelled or forfeited will be available for issuance under the 2024 Employee Plan or the 2024 Directors Plan, as applicable.

As of March 31, 2026, 5.5 million shares were available for issuance pursuant to awards that may be made in the future under stockholder-approved equity plans.

For the three months ended March 31, 2026 and 2025, stock-based compensation expense was $1.8 million and $3.2 million, respectively.

PSUs, RSUs and Restricted Stock

The following table summarizes the PSUs, RSUs and restricted stock outstanding as of December 31, 2025, and March 31, 2026 and the changes that occurred during the three months ended March 31, 2026:

	Number of Shares (in thousands)			Weighted Avg. Grant Date Fair Value (per share)
Unvested PSUs, RSUs and restricted stock outstanding, December 31, 2025		1,967		$	10.70
PSUs, RSUs and restricted stock granted		95		$	8.88
PSUs, RSUs and restricted stock vested		(487	)	$	11.50
PSUs, RSUs and restricted stock forfeited		(59	)	$	19.32
Unvested PSUs, RSUs and restricted stock outstanding, March 31, 2026		1,516		$	9.99

The fair value of PSUs with performance conditions, RSUs and restricted stock is equal to the closing price of the Company's stock on the date of grant. The fair value of PSUs with market conditions is calculated using a Monte Carlo simulation valuation method.

As of March 31, 2026, total unrecognized compensation expense related to non-vested portion of performance-based PSUs, market-based PSUs, RSUs and restricted stock was approximately $12.1 million, which will be recognized over the remaining weighted-average period of 2.2 years. Unrecognized compensation expense will be adjusted for actual forfeitures.