X0306 4 2017-04-03 0 0001651235 Acacia Communications, Inc. ACIA 0001385031 Commonwealth Capital Ventures IV L P 400 WEST CUMMINGS PARK SUITE 1725-134 WOBURN MA 01801 0 0 1 0 0001691343 Commonwealth Venture (GP) Partners IV LP 400 WEST CUMMINGS PARK SUITE 1725-134 WOBURN MA 01801 0 0 1 0 0001690558 Commonwealth Venture (GP) Partners IV LLC 400 WEST CUMMINGS PARK SUITE 1725-134 WOBURN MA 01801 0 0 1 0 Common Stock 2017-04-03 4 J 0 600000 D 4150915 D On April 3, 2017, Commonwealth Capital Ventures IV L.P. ("CCV IV") distributed, for no consideration, all 600,000 shares of the Issuer's Common Stock pro-rata to its partners, including its limited partners and its general partner, Commonwealth Venture (GP) Partners IV L.P. ("GP IV LP"), in accordance with the exemptions afforded by Rule 16a-9 and Rule 16a-13 of the Securities Exchange Act of 1934, as amended (the "Act"). Immediately following the distribution by CCV IV on the same date, GP IV LP distributed, for no consideration, the shares it received in the distribution by CCV IV to its limited partners, representing each such partner's pro rata interest in such shares, in accordance with the exemptions afforded by Rules 16a-13 and 16a-9 of the Act. Each of GP IV LP and Commonwealth Venture (GP) Partners IV LLC ("GP IV LLC"), its general partner, disclaims beneficial ownership of the shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that it is the beneficial owner of such shares. Commonwealth Capital Ventures IV L.P., By: Commonwealth Venture (GP) Partners IV L.P., its general partner, By: Commonwealth Venture (GP) Partners IV LLC, its general partner, By: /s/ Elliot Katzman, Manager 2017-04-05 Commonwealth Venture (GP) Partners IV L.P., By: Commonwealth Venture (GP) Partners IV LLC, its general partner, By: /s/ Elliot Katzman, Manager 2017-04-05 Commonwealth Venture (GP) Partners IV LLC, By: /s/ Elliot Katzman, Manager 2017-04-05