X0306 4/A 2021-11-17 2021-11-18 0 0000926282 ADTRAN INC ADTN 0001766181 Harris Ray 901 EXPLORER BOULEVARD HUNTSVILLE AL 35806 0 1 0 0 Chief Information Officer Common Stock 2021-11-17 4 A 0 4012 0 A 16648.31 D We previously reported that 4,215 restricted stock units were granted. The actual number of restricted stock units granted was 4,012. The revised amount of securities beneficially owned following this correction is 16,648.31. The restricted stock units vest in four equal and annual installments beginning on the first anniversary date of the grant. Michael Foliano, by power of attorney 2021-11-19