Sec Form 4 Filing - Section 32 Fund 1, LP @ Arsanis, Inc. - 2017-11-20

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 Section 32 Fund 1, LP 2. Issuer Name and Ticker or Trading Symbol Arsanis, Inc. [ ASNS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 2071 SAN ELIJO AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 11/20/2017 (Street) CARDIFF-BY-THE-SEA, CA92007 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ 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 11/20/2017 C 451,362 A 451,362 D ( 2 )

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 Series D Convertible Preferred Stock ( 1 ) 11/20/2017 C 1,540,500 ( 1 ) ( 1 ) Common Stock 451,362 $ 0 0 D ( 2 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Section 32 Fund 1, LP 2071 SAN ELIJO AVENUE CARDIFF-BY-THE-SEA, CA92007 X Section 32 GP 1, LLC 2071 SAN ELIJO AVENUE CARDIFF-BY-THE-SEA, CA92007 X Maris William J 2071 SAN ELIJO AVENUE CARDIFF-BY-THE-SEA, CA92007 X Signatures /s/ Mike Gray, attorney-in-fact on behalf of Section 32 Fund 1, LP 11/20/2015 Signature of Reporting Person Date /s/ Mike Gray, attorney-in-fact on behalf of Section 32 GP 1, LLC 11/20/2015 Signature of Reporting Person Date /s/ Mike Gray, attorney-in-fact on behalf of William J. Maris 11/20/2015 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The Series D Convertible Preferred Stock converted into Common Stock on a 0.29300-for-one basis upon the closing of the Issuer's initial public offering without payment of consideration. The Series D Convertible Preferred Stock was convertible at any time at the holder's election and automatically upon the closing at the Issuer's initial public offering. The shares had no expiration date. ( 2 )The reported securities are held of record by Section 32 Fund 1, LP ("Fund 1"). Section 32 GP 1, LLC (the "GP"), the general partner of Fund 1, and William J. Maris, the managing member of the GP, may be deemed to share voting and dispositive power over the shares held by Fund 1. Such persons and entities disclaim beneficial ownership of shares held by Fund 1 except to the extent of any pecuniary interest therein.

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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