In Merton (1987), idiosyncratic risk is priced in equilibrium as a consequence of incomplete diversification. We modify his model to allow the degree of diversification to vary with average idiosyncratic volatility. This simple recognition results in a state‐dependent...

Cusatis, Miles, and Woolridge (1993) report large positive excess returns following spin-offs over the period 1965-88. We investigate whether a trading strategy based on this ex post analysis would have earned excess returns on an ex ante basis over the period 1989-95. When compared with the...