X0306 4 2019-12-16 0001708055 Ribbon Communications Inc. RBBN 0001720719 McCready John R RIBBON COMMUNICATIONS INC. 4 TECHNOLOGY PARK DRIVE WESTFORD MA 01886 0 1 0 0 EVP and Chief Strategy Officer Common Stock 2019-11-29 4 A 0 500 2.4905 A 90849 D Common Stock 2019-12-16 4 M 0 4167 A 95016 D Common Stock 2019-12-16 4 S 0 1239 2.80 D 93777 D Restricted Stock Units 2019-12-16 4 M 0 4167 0 D Common Stock 4167 12499 D These shares were acquired under the Ribbon Communications Inc. Amended and Restated 2000 Employee Stock Purchase Plan in transactions that were exempt under both Rule 16b-3(d) and Rule 16b-3(c). Restricted stock units convert into common stock on a one-for-one basis. The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 instruction letter previously adopted by the Reporting Person and represent shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. 25,000 restricted stock units were granted to the Reporting Person on June 15, 2018, vesting over a three-year period. One-third of those restricted stock units vested on June 17, 2019, one-sixth vested on December 16, 2019 and the remainder of the restricted stock units will vest in three equal, semi-annual installments thereafter through June 15, 2021. John R. McCready 2019-12-18