X0306 4 2022-07-08 0 0000926282 ADTRAN Holdings, Inc. ADTN 0001201037 HUSS H FENWICK C/O ADTRAN HOLDINGS, INC. 901 EXPLORER BLVD. HUNTSVILLE AL 35806 1 0 0 0 Common Stock 2022-07-08 4 A 0 56415.53 A 56415.53 D Pursuant to that certain Business Combination Agreement, dated August 30, 2021, by and among ADTRAN, Inc., ADVA Optical Networking SE, the Issuer (f/k/a Acorn HoldCo, Inc., and Acorn MergeCo, Inc., ADTRAN, Inc. became a wholly owned subsidiary of the Issuer on July 8, 2022 (the "Effective Time"). At the Effective Time, each share of ADTRAN, Inc.'s common stock converted, on a one-for-one basis, into a share of the Issuer's common stock. Includes 3,943 shares of time-based restricted stock under a restricted stock award (an "RSA") and 35.53 shares of restricted stock acquired in connection with such RSA pursuant to a dividend reinvestment feature of the applicable equity plan. /s/ Michael Foliano, by power of attorney 2022-07-11