X0306 4 2016-12-06 0 0001123494 HARVARD BIOSCIENCE INC HBIO 0001230427 LEWIS EARL R 87 PINCKNEY STREET BOSTON MA 02114 1 0 0 0 Common Stock 2016-12-06 4 S 0 23088 2.42 D 392012 D The price reported above reflects the weighted average sales 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) a deferred stock award of 25,300 restricted stock units which fully vest on the earlier of (i) the date of the Issuer's next Annual Meeting of Stockholders after July 1, 2016, immediately prior to the commencement of such meeting, and (ii) July 1, 2017; (b) a deferred stock award of 6,350 restricted stock units which vests in full on December 31, 2016; and (c) 360,362 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 2016-12-07