If spin-offs are founded on intellectual capital accumulated at the parent firms, they could be potentially harmful to those firms. However, similar effects on parent firms' performance could be expected if key-employees depart for other reasons than spin-off entrepreneurship. Exploiting a comprehensive Danish linked employer-employee database, we investigate how spin-off and executive migration affect parent firms' hazard of exit, sales growth and employment growth. We find negative performance effects from executive migration independent on where employees go to. The negative effects are larger when key-employees resign to competing incumbent firms, and they are even greater when key-employees depart to spin-off entrepreneurship. However, the negative effects on parent firms' performance decrease with time. This happens faster in the case of spin-off, eventually making the overall negative performance effects from spin-off smaller than for executive migration in general.