This article investigates the implications of separation of ownership and control for board composition over a spectrum of ownership structures present in the U.S. property–liability insurance industry. We hypothesize that agency costs associated with manager–owner conflicts increase with the degree of separation of ownership and control. Greater agency costs imply a greater need for monitoring by outside directors on the board. Therefore, use of outside directors is expected to increase as the separation of ownership and control gets larger. Employing a sample of property–liability insurers exhibiting different degrees of separation of ownership and control, we find support for our hypothesis.