X0306 4 2015-03-24 0 0001374690 ZAFGEN, INC. ZFGN 0001346450 Atlas Venture Fund VII L P 25 FIRST STREET, SUITE 303 CAMBRIDGE MA 02141 0 0 1 0 0001377726 Atlas Venture Associates VII, L.P. 25 FIRST STREET, SUITE 303 CAMBRIDGE MA 02141 0 0 1 0 0001377725 Atlas Venture Associates VII, Inc. 25 FIRST STREET, SUITE 303 CAMBRIDGE MA 02141 0 0 1 0 Common Stock 2015-03-24 4 J 0 1000000 0 D 4632730 D On March 24, 2015, Atlas Venture Fund VII LP ("Atlas Venture") distributed in-kind, without consideration, all 1,000,000 shares of the Issuer's Common Stock, pro-rata, to its limited partners. These shares were held directly by Atlas Venture. The general partner of Atlas Venture is Atlas Venture Associates VII, L.P. ("AVA VII LP"), and the general partner of AVA VII LP is Atlas Venture Associates VII, Inc. ("AVA VII Inc."). AVA VII LP and AVA VII Inc. disclaim beneficial ownership of such shares, except to the extent of a pecuniary interest, if any, therein. By: Atlas Venture Fund VII LP, By: Atlas Venture Associates VII, L.P., its general partner, By: Atlas Venture Associates VII, Inc., its general partner, /s/ Frank Castellucci, Secretary 2015-03-26 By: Atlas Venture Associates VII, L.P., By: Atlas Venture Associates VII, Inc., its general partner, /s/ Frank Castellucci, Secretary 2015-03-26 By: Atlas Venture Associates VII, Inc., /s/ Frank Castellucci, Secretary 2015-03-26