Statement of Changes in Beneficial Ownership (4)

FORM 4 [ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response... 0.5
	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person * Mikkelsen Benny P	2. Issuer Name and Ticker or Trading Symbol Acacia Communications, Inc. [ ACIA ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __ X __ Director                      _____ 10% Owner __ X __ Officer (give title below)      _____ Other (specify below) Chief Technology Officer
(Last)          (First)          (Middle) C/O ACACIA COMMUNICATIONS, INC., THREE MILL AND MAIN PLACE, SUITE 400	3. Date of Earliest Transaction (MM/DD/YYYY) 10/12/2016
(Street) MAYNARD, MA 01754 (City)        (State)        (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) _ X _ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. Code (Instr. 8)		4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	10/12/2016		F (1)		19446	D	$88.46	1143452   (2)	D
Common Stock	10/13/2016		S (3)		98846	D	$96.50	1044606   (4)	D

Table II - Derivative Securities Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:
( 1)	Represents shares of common stock that have been withheld by the Company to satisfy its income tax withholding obligations in connection with the vesting of restricted stock units ("RSUs") that were previously reported by the Reporting Person and does not represent a sale by the Reporting Person. Each RSU represents the right to receive one share of common stock upon vesting.
( 2)	Consists of 1,020,279 shares of common stock and 123,173 RSUs.
( 3)	The sale transaction reported on this Form 4 was effected as part of an underwritten public offering of common stock of the Company in which the Reporting Person was a selling stockholder.
( 4)	Consists of 921,433 shares of common stock and 123,173 RSUs.

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Mikkelsen Benny P C/O ACACIA COMMUNICATIONS, INC. THREE MILL AND MAIN PLACE, SUITE 400 MAYNARD, MA 01754	X		Chief Technology Officer

Signatures
/s/ Janene I. Asgeirsson, attorney-in-fact		10/14/2016
** Signature of Reporting Person		Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note:	File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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