X0306 4 2019-08-09 0 0001123494 HARVARD BIOSCIENCE INC HBIO 0001400121 Green James W C/O HARVARD BIOSCIENCE, INC. 84 OCTOBER HILL ROAD HOLLISTON MA 01746 1 1 0 0 Chief Executive Officer Common Stock 2019-08-09 4 A 0 20000 2.466 A 1515404 I by James W. Green Revocable Trust This transaction was executed in multiple trades at prices ranging from $2.43 to $2.49, inclusive. The price reported above reflects the weighted average purchase price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. Includes (a) deferred stock award of 35,100 restricted stock units which fully vest on the earlier of (i) the date of the Issuer's next Annual Meeting of Stockholders after May 16, 2019, immediately prior to the commencement of such meeting, and (ii) May 23, 2020; (b) a deferred stock award of 202,875 restricted stock units which shall fully vest on July 8, 2020; (c) a deferred stock award of 243,072 restricted stock units which shall fully vest on July 8, 2021; (d) a deferred stock award of 418,360 restricted stock units which shall vest in four equal installments on January 1, 2020, 2021, 2022 and 2023; (e) a deferred stock award of 418,360 restricted stock units with performance based vesting conditions tied to relative total shareholder return; and (f) 197,637 shares of common stock beneficially owned by the Reporting Person. This form has been signed under power of attorney. /s/ Chad Porter, by power of attorney 2019-08-12