X0306 4 2018-05-06 0 0001123494 HARVARD BIOSCIENCE INC HBIO 0001504983 Gagnon Robert E. C/O HARVARD BIOSCIENCE, INC. 84 OCTOBER HILL ROAD HOLLISTON MA 01746 0 1 0 0 Chief Financial Officer Common Stock 2018-05-06 4 F 0 26081 5.00 D 331857 D The shares were disposed to satisfy the Reporting Person's tax withholding obligation in connection with deferred stock awards previously granted to the Reporting Person which vested on May 6, 2018. Includes (a) a deferred stock award of 81,522 restricted stock units which shall vest in three equal installments on January 1, 2019, 2020 and 2021; (b) a deferred stock award of 108,696 restricted stock units which shall vest in full on May 25, 2019; (c) a deferred stock award of 44,326 restricted stock units which shall vest in two equal installments on January 1, 2019 and 2020; (d) a deferred stock award of 6,625 restricted stock units which shall vest in full on January 1, 2019; (e) a deferred stock award of 28,117 restricted stock units with performance based vesting conditions, which shall vest on August 3, 2018 contingent upon achievement of a performance condition tied to relative total shareholder return; and (f) 62,571 shares of common stock held by the Reporting Person. This form has been signed under power of attorney. /s/ Chad Porter, by power of attorney 2018-05-08