Certain Restricted Stock Units of Acacia Communications, Inc. are subject to a Lock-Up Agreement Ending on 4-JAN-2017. These Restricted Stock Units will be under lockup for 90 days starting from 6-OCT-2016 to 4-JAN-2017. Details: The company, selling stockholders, and each of the directors and executive officers and entities with which they are affiliated, collectively holding 29,327,377 shares as of the date of this prospectus, have agreed that, without the prior written consent of Goldman, Sachs & Co., Merrill Lynch, Pierce, Fenner & Smith Incorporated, Deutsche Bank Securities Inc. and Morgan Stanley & Co. LLC, they will not offer, sell, contract to sell, pledge, grant any option to purchase, make any short sale or otherwise dispose of any shares of common stock, any options or warrants to purchase any shares of common stock or any securities convertible into, exchangeable for or that represent the right to receive shares of common stock for a period of 90 days after the date of the initial prospectus.