Sec Form 4 Filing - MCCOURT Thomas A @ IRONWOOD PHARMACEUTICALS INC - 2018-12-31

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 MCCOURT Thomas A 2. Issuer Name and Ticker or Trading Symbol IRONWOOD PHARMACEUTICALS INC [ IRWD] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Commercial Officer (Last) (First) (Middle) C/O IRONWOOD PHARMACEUTICALS, INC., 301 BINNEY STREET 3. Date of Earliest Transaction (MM/DD/YY) 12/31/2018 (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 Class A Common Stock 88,150 D

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 Employee Stock Option (Right to Buy) $ 5.48 12/31/2018 J( 1 ) 130,000 ( 2 ) 09/07/2019 Class B Common Stock 130,000 ( 1 ) 0 D Employee Stock Option (Right to Buy) $ 5.48 12/31/2018 J( 1 ) 130,000 ( 2 ) 09/07/2019 Class A Common Stock 130,000 ( 1 ) 130,000 D Employee Stock Option (Right to Buy) $ 5.48 12/31/2018 J( 1 ) 130,000 ( 3 ) 09/07/2019 Class B Common Stock 130,000 ( 1 ) 0 D Employee Stock Option (Right to Buy) $ 5.48 12/31/2018 J( 1 ) 130,000 ( 3 ) 09/07/2019 Class A Common Stock 130,000 ( 1 ) 130,000 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other MCCOURT Thomas A C/O IRONWOOD PHARMACEUTICALS, INC. 301 BINNEY STREET CAMBRIDGE, MA02142 Chief Commercial Officer Signatures /s/ Conor Kilroy, Attorney-In-Fact 01/03/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On December 31, 2018, each share of the Issuer's outstanding Class B Common Stock automatically converted into one share of the Issuer's Class A Common Stock pursuant to the Issuer's certificate of incorporation. In connection with the conversion, outstanding stock options granted pursuant to the Issuer's equity incentive plans in respect of the Issuer's Class B Common Stock remain unchanged, except that they now represent the right to receive shares of Class A Common Stock rather than shares of Class B Common Stock. ( 2 )The option vested as to 25% of the shares of Class B Common Stock on the first anniversary of September 8, 2009, and 1/48th of the shares of Class B Common Stock vest each month thereafter for the next 36 months. The option was fully vested as of September 8, 2013. ( 3 )The option vests in four equal installments based on the issuer's achievement of certain regulatory and commercial milestones. Upon achievement of regulatory or commercial milestones, the option vested as to 40,000 shares of Class B Common Stock on each of October 24, 2011, December 21, 2012 and January 4, 2017.

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