X0306 4 2022-08-11 0 0000926282 ADTRAN Holdings, Inc. ADTN 0001191219 STANTON THOMAS R C/O ADTRAN 901 EXPLORER BLVD. HUNTSVILLE AL 35806 1 1 0 0 Chairman and CEO Common Stock 2022-08-11 4 M 0 5893 16.97 A 847975.09 D Common Stock 2022-08-11 4 F 0 4124 24.25 D 843851.09 D Common Stock 2022-08-11 4 M 0 69473 16.97 A 913324.09 D Common Stock 2022-08-11 4 F 0 57867 24.25 D 855457.09 D Incentive Stock Option (Right to Buy) 16.97 2022-08-11 4 M 0 5893 0 D 2022-11-06 Common Stock 5893 0 D Non-Qualified Stock Option (Right to Buy) 16.97 2022-08-11 4 M 0 69473 0 D 2022-11-06 Common Stock 69473 0 D Phantom Stock Common Stock 158297.672 158297.672 D Represents shares surrendered to Adtran Holdings, Inc. to cover the exercise price of outstanding stock options. The reporting person received 1,769 shares of common stock on the net exercise of stock options to purchase 5,893 shares of common stock. The reporting person surrendered 4,124 shares of common stock underlying the stock options for payment of the exercise price, using the closing stock price on August 10, 2022 of $24.25, pursuant to the terms of the 2006 Employee Stock Incentive Plan. Represents shares surrendered to Adtran Holdings, Inc. to cover the exercise price of outstanding stock options. The reporting person received 11,606 shares of common stock on the net exercise of stock options to purchase 69,473 shares of common stock. The reporting person surrendered 57,867 shares of common stock underlying the stock options for payment of the exercise price and tax withholding, using the closing stock price on August 10, 2022 of $24.25, pursuant to the terms of the 2006 Employee Stock Incentive Plan. The options granted to the reporting person vested in four annual installments beginning on the anniversary of the date of grant and were fully vested prior to the Effective Time. Represents shares of phantom stock of the Issuer that have been acquired through the automatic reinvestment of dividends paid on the Issuer's common stock, which phantom shares become payable in cash six months after the reporting person's separation of service with the Issuer. Michael Foliano, by power of attorney 2022-08-15