X0306 4 2021-03-15 0001708055 Ribbon Communications Inc. RBBN 0001720721 Marmurek Eric S C/O RIBBON COMMUNICATIONS INC. 6500 CHASE OAKS BOULEVARD, SUITE 100 PLANO TX 75023 0 1 0 0 SVP, CAO Common Stock 2021-03-16 4 M 0 30865 0.0 A 64399 D Common Stock 2021-03-16 4 F 0 7482 8.65 D 56917 D Restricted Stock Units (RSUs) 2021-03-15 4 A 0 24700 0.0 A Common Stock 24700 24700 D Performance-Based Restricted Stock Units (PSUs) 2021-03-15 4 A 0 14820 0.0 A Common Stock 14820 14820 D PSUs 2021-03-15 4 A 0 9880 0.0 A Common Stock 9880 9880 D RSUs 2021-03-16 4 M 0 30865 0 D Common Stock 30865 61728 D RSUs convert into 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. Each RSU represents a contingent right to receive one share of the Issuer's common stock. The RSUs will vest as to one-third on March 15, 2022 and the remaining two-thirds of the RSUs will vest in four equal semi-annual installments thereafter through March 15, 2024. Each PSU represents a contingent right to receive one share of the Issuer's Common Stock. The number of PSUs earned and issuable upon vesting will be determined based on goals set by the Compensation Committee of the Issuer's Board of Directors (the "Compensation Committee") on an annual basis for each of the three fiscal years prior to the vesting date. The aggregate number of shares issued may range from zero shares to 200% of the target number of shares reported in columns 5, 7 and 9 of Table II. The number of PSUs reported in columns 5, 7 and 9 of Table II reflects achievement at the target level of performance. This PSU will vest on 3/15/2024. Each PSU represents a contingent right to receive one share of the Issuer's Common Stock, based on the Issuer's total shareholder return (TSR) compared to pre-established relative TSR goals, based on the TSR of a peer index of companies set by the Compensation Committee over the three fiscal years ending prior to the vesting date. The aggregate number of shares issued may range from zero shares to 200% of the target number of shares reported in columns 5, 7 and 9 of Table II. The number of PSUs reported in columns 5, 7 and 9 of Table II reflects achievement at the target level of performance. This PSU will vest on 3/15/2024. On March 16, 2020, the Reporoting Person was awarded 92,593 RSUs which vested as to one-third on March 16, 2021. The remaining RSUs vest in four equal semi-annual installments thereafter through March 16, 2023. Patrick Macken, Attorney-in-Fact 2021-03-17