Principal-Agent Theory Principal-agent theory (also: agency theory) describes strategic interactions between at least two contract partners, called the principal and the agent (e.g., Jensen and Meckling 1976; Arrow 1985; Eisenhardt 1989; Halachmi 2004). The agent acts on behalf of the principal. Typical examples are employer/employee relationships or those between shareholders/owners and management teams. Basic assumptions are that the actors are utility maximizers driven by self-interest who act in situations of bounded rationality and normally differ in their risk aversion (Jensen & Meckling 1976; Eisenhardt 1989). Principal-agent theory is concerned with two problems: Firstly, the conflict of goals between the principal and the agent, and secondly, the difficulty or cost born by the principal to verify what the agent is actually doing (Eisenhardt 1989). According to Jensen and Meckling (1976, 311) three types of agency costs occur: Monitoring expenditures by the principal, bonding expenditures by the agent, and a residual loss caused by the divergence between the agent’s decisions and those decisions which would have maximized the principal’s welfare.