Equilibrium Model Asset Pricing Moral Hazard

  • 详情 An Equilibrium Model of Asset Pricing and Moral Hazard
    This paper develops an integrated model of asset pricing and moral hazard. In particular, we combine a version of the Capital Asset Pricing Model (CAPM) with a multi-agent moral hazard model. The excess dollar returns for risky stocks, optimal contracts for managers (agents) that involve relative performance, and equilibrium stock prices are explicitly characterized. We show that the CAPM linear relation in terms of the expected dollar returns still holds in the presence of moral hazard and that our is given by the ratio of the covariance between a firm’s stock return and the market return over the variance of the market return, with both returns adjusted for the compensation to the managers. The equilibrium price of a stock decreases with its idiosyncratic risk, but the expected excess dollar return of the stock is independent of it. Consequently, the risk premium, which is defined as the ratio of the excess return to the stock price, increases with idiosyncratic risk. We also show that the risk aversion of the principal in our model leads to less emphasis on relative performance evaluation than in a model with a risk-neutral principal. This result may shed light on why the empirical evidence for relative performance evaluation is mixed, even though the theoretical prediction based on a risk-neutral principal strongly supports it. In addition, we show that if the manager of a firm is compensated based solely on his own performance, then the expected dollar return of the firm increases with its idiosyncratic risk. This exercise illustrates that, in the presence of moral hazard, contracting plays a key role in the determination of the expected return of a stock. Furthermore, we show that under certain conditions, the equilibrium contract is a linear combination of the stock price and the level of the market portfolio.