X0306 4 2016-09-15 0 0001446847 IRONWOOD PHARMACEUTICALS INC IRWD 0001117003 MCGUIRE TERRANCE C/O IRONWOOD PHARMACEUTICALS, INC. 301 BINNEY STREET CAMBRIDGE MA 02142 1 0 0 0 Class A Common Stock 2016-09-15 4 A 0 166 0.00 A 44253 D Class A Common Stock 1626 I By Polaris Venture Management Co. II, L.L.C. Class A Common Stock 29117 I By Bartlett Partners, LLC Class B Common Stock 40000 I By Bartlett Partners, LLC Issued pursuant to the Director Compensation Plan, effective as of January 2014. The reporting person is a managing member of Polaris Venture Management Co. II, L.L.C., the beneficial owner of the securities. The reporting person disclaims beneficial ownership of the reported securities, except to the extent of his pecuniary interest therein. The reporting person is a managing member of Bartlett Partners, LLC, the beneficial owner of the securities. The reporting person disclaims beneficial ownership of the securities, except to the extent of his pecuniary interest therein. /s/ Mark Gaffney, Attorney-in-Fact 2016-09-19