X0306 4 2016-05-18 1 0001651235 Acacia Communications, Inc. ACIA 0000830588 SUMMIT PARTNERS L P 222 BERKELEY STREET 18TH FLOOR BOSTON MA 02116 0 0 1 1 Manager of GP of 10% owner 0001665677 SUMMIT PARTNERS VC III, LP 222 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 0 0 0 1 GP of 10% owner 0001665675 SUMMIT PARTNERS VC III, LLC 222 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 0 0 0 1 Manager of GP of 10% owner 0001627278 SUMMIT MASTER COMPANY, LLC 222 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 0 0 0 1 Manager of Manager of 10% owne 0001507545 Summit Investors Management, LLC 222 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 0 0 0 1 Manager and GP of 10% Owner 0001514390 Summit Partners Venture Capital Fund III-A, L.P. 222 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 0 0 1 0 0001514389 Summit Partners Venture Capital Fund III-B, L.P. 222 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 0 0 1 0 0001435565 Summit Investors I, LLC 222 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 0 0 1 0 0001494616 Summit Investors I (UK), L.P. 222 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 0 0 1 0 Common Stock 2016-05-18 4 C 0 2896329 A 2896329 I See Footnotes. Series D Convertible Preferred Stock 2016-05-18 4 C 0 2896329 0 A Common Stock 2896329 0 I See Footnotes The Series D Convertible Preferred Stock converted into common stock on a one-for-one basis upon the closing of Acacia Communications, Inc.'s (the "Issuer") initial public offering without payment of consideration. The Series D Convertible Preferred Stock had no expiration date. Consists of 2,198,853 shares held by Summit Partners Venture Capital Fund III-A. L.P., 666,442 shares held by Summit Partners Venture Capital Fund III-B, L.P., 28,648 shares held by Summit Investors I, LLC and 2,386 shares held by Summit Investors I (UK), L.P. Summit Partners, L.P. is the managing member of Summit Partners VC III, LLC, which is the general partner of Summit Partners VC III, L.P., which is the general partner of each of Summit Partners Venture Capital Fund III-A. L.P. and Summit Partners Venture Capital Fund III-B, L.P. Summit Master Company, LLC is the managing member of Summit Investors Management, LLC, which is the manager of Summit Investors I, LLC, and the general partner of Summit Investors I (UK), L.P. Summit Master Company, LLC, as the managing member of Summit Investors Management, LLC, has delegated investment decisions, including voting and dispositive power, to Summit Partners, L.P. and its investment committee responsible for voting and investment decisions with respect to the Issuer. Summit Partners, L.P., through a three-person investment committee responsible for voting and investment decisions with respect to the Issuer, currently comprised of Martin J. Mannion, Bruce R. Evans and Peter Y. Chung, has voting and dispositive power over the shares held by each of these entities and therefore may be deemed to beneficially own such shares. Each of the Summit entities mentioned herein and Messrs. Mannion, Evans and Chung disclaims beneficial ownership of the shares, except, in each case, to the extent of each such person's pecuniary interest therein. Summit Partners, L.P., by Summit Master Company, LLC, its GP, by /s/ Robin W. Devereux, Member 2016-05-20 Summit Partners VC III, L.P., by Summit Partners VC III, LLC, its GP, by Summit Partners, L.P., its Managing Member, by Summit Master Company, LLC, its GP, by /s/ Robin W. Devereux, Member 2016-05-20 Summit Partners VC III, LLC, by Summit Partners, L.P., its Managing Member, by Summit Master Company, LLC, its GP, by /s/ Robin W. Devereux, Member 2016-05-20 Summit Master Company, LLC, by /s/ Robin W. Devereux, Member 2016-05-20 Summit Investors Management, LLC, by Summit Master Company, LLC, its Managing Member, by /s/ Robin W. Devereux, Member 2016-05-20 Summit Partners Venture Capital Fund III-A, L.P., by Summit Partners VC III, L.P., its GP, by Summit Partners VC III, LLC, its GP, by Summit Partners, L.P., its Managing Member, by Summit Master Company, LLC, its GP, by /s/ Robin W. Devereux, Member 2016-05-20 Summit Partners Venture Capital Fund III-B, L.P., by Summit Partners VC III, L.P., its GP, by Summit Partners VC III, LLC, its GP, by Summit Partners, L.P., its Managing Member, by Summit Master Company, LLC, its GP, by /s/ Robin W. Devereux, Member 2016-05-20 Summit Investors I, LLC, by Summit Investors Management, LLC, its Manager, by Summit Master Company, LLC, its Managing Member, by /s/ Robin W. Devereux, Member 2016-05-20 Summit Investors I (UK), L.P., by Summit Investors Management, LLC, its General Partner, by Summit Master Company, LLC, its Managing Member, by /s/ Robin W. Devereux, Member 2016-05-20