Sec Form 4 Filing - Soni Manmeet Singh @ ALNYLAM PHARMACEUTICALS, INC. - 2018-08-13

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 Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Soni Manmeet Singh 2. Issuer Name and Ticker or Trading Symbol ALNYLAM PHARMACEUTICALS, INC. [ ALNY] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Financial Officer (Last) (First) (Middle) 300 THIRD STREET 3. Date of Earliest Transaction (MM/DD/YY) 08/13/2018 (Street) CAMBRIDGE, MA02142 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction 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 07/25/2017 J( 1 ) V 2 A $ 0 ( 1 ) 2 I by Managed Account ( 1 ) Common Stock 10/16/2017 J( 1 ) V 11 A $ 0 ( 1 ) 13 I by Managed Account ( 1 ) Common Stock 01/17/2018 J( 1 ) V 6 A $ 0 ( 1 ) 19 I by Managed Account ( 1 ) Common Stock 04/16/2018 J( 1 ) V 28 A $ 0 ( 1 ) 47 I by Managed Account ( 1 ) Common Stock 07/10/2018 J( 1 ) V 36 A $ 0 ( 1 ) 83 I by Managed Account ( 1 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction 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 (MM/DD/YY) 7. Title and Amount of Underlying Securities (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 Performance Stock Option 2017 (right to buy) $ 52.61 08/13/2018 A( 2 ) 25,000 08/13/2018 05/08/2027 Common Stock 25,000 $ 0 25,000 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Soni Manmeet Singh 300 THIRD STREET CAMBRIDGE, MA02142 Chief Financial Officer Signatures By: /s/ Michael P. Mason, Attorney-in-Fact For: Manmeet S Soni 08/14/2018 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Reflects shares of ALNY common stock acquired by the reporting person under the ALNY 401(k) plan as a result of the ALNY 401(k) matching contribution program. ( 2 )On May 8, 2017, the reporting person was granted a performance based stock option to purchase shares of ALNY common stock. The shares subject to the option will vest upon the commercial launch of Alnylams first internally developed product, as approved by our compensation committee. Effective August 13, 2018, the compensation committee of the Company determined the performance criterion has been met and the option shares have vested.

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).

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