A dynamic CAPM with supply effect: Theory and empirical results

Abstract

Breeden [Breeden, D. T. (1979). An intertemporal asset pricing model with stochastic consumption and investment opportunities. Journal of Financial Economics 7, 265–196] and Grinols [Grinols, E. L. (1984). Production and risk leveling in the intertemporal capital asset pricing model. The Journal of Finance 39, 5, 1571–1595] and Cox et al. [Cox, J. C., Ingersoll, J. E., Jr., & Ross, S. A. (1985). An intertemporal general equilibrium model of asset prices. Econometrica 53, 363–384] have described the importance of supply side for the capital asset pricing. Black [Black, S. W. (1976). Rational response to shocks in a dynamic model of capital asset pricing. American Economic Review 66, 767–779] derives a dynamic, multiperiod CAPM, integrating endogenous demand and supply. However, Black's theoretically elegant model has never been empirically tested for its implications in dynamic asset pricing. We first theoretically extend Black's CAPM. Then we use price, dividend per share and earnings per share to test the existence of supply effect with U.S. equity data. We find the supply effect is important in U.S. domestic stock markets. This finding holds as we break the companies listed in the S&P 500 into ten portfolios by different level of payout ratio. It also holds consistently if we use individual stock data.