X0306 4 2022-03-03 0 0000926282 ADTRAN INC ADTN 0001637150 Jacqueline Hourigan Rice 901 EXPLORER BOULEVARD HUNTSVILLE AL 35806 1 0 0 0 Dividend Equivalent Rights 2022-03-03 4 A 0 17.507 20.27 A Common Stock 17.507 17.507 D Dividend equivalent rights accrue when and as dividends are paid on the Company's common stock. The rights are paid in whole shares of common stock with the remainder paid in cash upon vesting of restricted stock units. Each dividend equivalent right is the equivalent of one share of the Company's common stock. Erika Huber, by power of attorney 2022-03-07