X0306 4 2017-02-16 0 0000907654 ARCA biopharma, Inc. ABIO 0001454996 Ozeroff Christopher David 11080 CIRCLEPOINT ROAD SUITE 140 WESTMINSTER CO 80020 0 1 0 0 S.V.P., General Counsel Common Stock 18400 D Stock Option (right to buy) 2.50 2017-02-16 4 A 0 24000 0.00 A 2027-02-15 Common Stock 24000 24000 D Includes (i) remaining 2,443 previously reported shares issued as Restricted Stock Units ("RSUs") under the 2013 Amended and Restated Equity Incentive Plan (the "Plan") that vest in two equal annual installments beginning on 2/27/17, and (ii) 2,290 previously reported shares issued as RSUs under the Plan that vest in two equal annual installments beginning 4/2/17, provided that the Reporting Person's continuous service to the Issuer has not been terminated as defined under the Plan; and 13,667 previously reported shares of common stock held directly. Grant to the Reporting Person of a stock option under the Plan, vesting in 36 equal monthly installments from the date of grant, provided that the Reporting Person's continuous service to the Issuer has not been terminated as defined in or as determined under the Plan prior to such time. In the event of a change in control of the Issuer, 50% of the unvested options shall become fully and immediately vested upon the closing date of such change in control, provided, however, that on the earlier of (i) the one-year anniversary of the closing date or (ii) involuntary termination, any options that remain unvested on such earlier date shall become fully and immediately vested. /s/ Brian L. Selby, Attorney-in-Fact 2017-02-21