X0508 4 2023-09-05 0 0000926282 ADTRAN Holdings, Inc. ADTN 0001191219 STANTON THOMAS R C/O ADTRAN HOLDINGS, INC. 901 EXPLORER BOULEVARD HUNTSVILLE AL 35806-2807 1 1 0 0 Chairman & CEO 0 Phantom Stock 2023-09-05 4 A 0 2340.361 A Common Stock 2340.361 225774.587 D Stock Options 15.33 2023-11-14 Common Stock 94207 94207 D Stock Options 18.97 2024-11-15 Common Stock 94207 94207 D Stock Options 23.64 2023-11-02 Common Stock 75366 75366 D 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 held in the reporting person's account under the Issuer's equity deferral program. The phantom shares are issued to the reporting person six months after a separation of service from the Issuer in the form of whole shares of common stock, plus cash for any fractional shares. The options granted to the reporting person vested in four equal annual installments beginning on November 14, 2015. The options granted to the reporting person vested in four equal annual installments beginning on November 15, 2014 The options granted to the reporting person vested in four equal annual installments beginning on November 2, 2013. /s/ Dan Ragsdale, by power of attorney 2023-09-07