Statement of Changes in Beneficial Ownership (4)

FORM 4 [X] 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
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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 ^* Givehchi Mehrdad	2. Issuer Name and Ticker or Trading Symbol Acacia Communications, Inc. [ ACIA ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) VP of Hardware and Software
(Last) (First) (Middle) C/O ACACIA COMMUNICATIONS, INC., THREE MILL AND MAIN PLACE, SUITE 400	3. Date of Earliest Transaction (MM/DD/YYYY) 3/1/2021
(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)
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	3/1/2021		A		11541	A	⁽¹⁾	329092 ⁽²⁾	D
Common Stock	3/1/2021		D		11541	D	⁽¹⁾	317551 ⁽²⁾	D
Common Stock	3/1/2021		D		298316	D	$115 ⁽³⁾	19235 ⁽²⁾	D
Common Stock	3/1/2021		D		19235	D	⁽²⁾	0	D
Common Stock	3/1/2021		D		245670	D	$115 ⁽³⁾	0	I	By Givehchi LLC

*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)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)			11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:
(1)	Represents a performance-based stock unit ("PSU") award that vested with respect to 11,541 shares of common stock in accordance with its terms immediately prior to the Merger on March 1, 2021, which PSUs were granted to the reporting person on February 14, 2019 and were subject to performance conditions that have been satisfied. Pursuant to the terms of the Merger Agreement, each outstanding performance-based restricted stock unit award that has vested in accordance with is terms immediately prior to the Merger and has not yet been settled was automatically terminated and converted at the Effective Time into the right to receive the Merger Consideration for each underlying share.
(2)	Includes restricted stock unit ("RSU") awards that were unvested with respect to 19,235 shares of common stock immediately prior to the Merger. Each RSU represents the right to receive one share of common stock upon vesting. Pursuant to the terms of the Merger Agreement, each outstanding RSU award that was unvested immediately prior to the Merger was automatically terminated and converted at the Effective Time into the right to receive the Merger Consideration for each underlying share; provided that right to receive payment of such amount remains subject to vesting under the schedule in place for such RSU immediately prior to the Effective Time, including under the terms of the Company's Amended and Restated Severance and Change in Control Benefits Plan and any scheduled retention agreement after giving effect to any applicable employment offer documents entered into with Parent.
(3)	Pursuant to the Merger Agreement, at the Effective Time, each share of the Company's common stock automatically converted into the right to receive the Merger Consideration.

Remarks:
On March 1, 2021, pursuant to the Amended and Restated Agreement and Plan of Merger, by and among Cisco Systems, Inc. ("Parent"), Amarone Acquisition Corp. ("Merger Sub") and Acacia Communications, Inc. (the "Company"), dated January 14, 2021 (the "Merger Agreement"), Merger Sub merged with and into the Company (the "Merger"), with the Company surviving the Merger as a wholly owned subsidiary of Parent. Pursuant to the Merger Agreement, at the effective time of the Merger (the "Effective Time"), each share of the Company's common stock automatically converted into the right to receive $115.00 per share in cash (the "Merger Consideration").

Reporting Owners
Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
Givehchi Mehrdad C/O ACACIA COMMUNICATIONS, INC. THREE MILL AND MAIN PLACE, SUITE 400 MAYNARD, MA 01754			VP of Hardware and Software