X0306 4 2021-06-03 0 0000926282 ADTRAN INC ADTN 0001300513 Foliano Michael 901 EXPLORER BLVD HUNTSVILLE AL 35806 0 1 0 0 CFO Common Stock 2021-06-03 4 A 0 1.043 18.29 A 243.774 I 401(k) Plan Phantom Stock 2021-06-03 4 A 0 92.416 20.11 A Common Stock 92.416 20741.123 D Reflects shares acquired through the automatic reinvestment of dividends paid on the Company's common stock. Each share of phantom stock represents a right to receive one share of common stock at the cash value thereof. The phantom stock becomes payable six months after the reporting person's separation of service with the Company. The reporting person may transfer the phantom stock account into an alternative investment at any time. Amy Moss, by power of attorney 2021-06-04