X0306 4 2020-03-05 0 0000926282 ADTRAN INC ADTN 0001371377 Wilson James Denson Jr 901 EXPLORER BLVD HUNTSVILLE AL 35806 0 1 0 0 Chief Revenue Officer Common Stock 3878.34 I 401(k) plan Common Stock 2020-03-05 4 A 0 41.218 0 A 3919.56 I 401(k) plan Phantom Stock 2020-03-05 4 A 1 179.735 0 A Common Stock 179.735 16350.955 D Shares held in 401(k) plan by Reporting Person. 109.879 of these shares of common stock were previously reported as phantom stock and therefore should have been reported in Table I. Dividends reinvested into common stock and held in 401(k) plan by Reporting Person. Each share of phantom stock represents a right to receive one share of common stock at the cash value thereof. Phantom stock held in a deferred compensation plan by the Reporting Person, which becomes payable six months after the Reporting Person's separation of service with the Company. The Reporting Person may transfer the phantom stock into an alternative investment at any time. Amy Moss, by power of attorney 2020-03-09