X0306 4 2022-03-15 0001708055 Ribbon Communications Inc. RBBN 0001720721 Marmurek Eric S C/O RIBBON COMMUNICATIONS 6500 CHASE OAKS BLVD., SUITE 100 PLANO TX 75023 0 1 0 0 SVP, Finance & CAO Common Stock 2022-03-15 4 M 0 8234 A 85991 D Common Stock 2022-03-15 4 A 0 11301 A 97292 D Common Stock 2022-03-15 4 M 0 11047 A 108339 D Common Stock 2022-03-15 4 F 0 8386 2.81 D 99953 D Common Stock 2022-03-16 4 M 0 15432 A 115385 D Common Stock 2022-03-16 4 F 0 3663 2.99 D 111772 D Restricted Stock Units (RSU) 2022-03-15 4 M 0 8234 0 D Common Stock 8234 16466 D Performance-based Restricted Stock Unit (PSUs) 2022-03-15 4 M 0 11047 0 D Common Stock 11047 0 D Restricted Stock Unit (RSU) 2022-03-16 4 M 0 15432 0 D Common Stock 15432 30864 D RSUs convert to Common Stock on a one-for-one basis. Reflects shares of Common stock withheld by the Issuer to satisfy tax withholding obligations in connection with the vesting of RSUs and/or PSUs. The RSU vested as to one third on March 15, 2022 and the remaining two-thirds will vest in four equal semi-annual installments thereafter through March 15, 2024 The RSUs originally vested as to one third on March 16, 2021, and the remaining two-thirds will vest in four equal semi-annual installments thereafter through March 16, 2023. PSUs that convert to Common Stock on a one-for-one basis based on the achievement of financial metrics in each of the 2019, 2020 and 2021 fiscal years establised by the Issuer's Compensation Committee of it's Board of Directors (Compensation Committee) at the time of grant. The PSUs then vested on March 15, 2022. Any unearned shares were forefeited. PSUs that convert to Common Stock on a one-for-one basis based on the achievement of the Issuer's total sharholder return (TSR) for the 3-year period ended December 31, 2021 compared to TSR goals established by the Compensation Committee at the time of grant based on the TSR of a group of peer companies identified by the Compensation Committee. The PSUs then vested on March 15, 2022. Any unearned shares were forefeited. Patrick Macken, Attorney-in-Fact 2022-03-17