In the standard CAPM with a riskless asset we prove existence of equilibria without assuming concavity of the investor's utility functions. Moreover, we give a uniqueness result using assumptions on the risk aversion of investors.

We demonstrate that in a CAPM economy Walras Law and the Tobin Separation Property characterize market demand in finite sets of prices. Consequently, for any number n there exist CAPM economies which have at least n equilibria and hence have n different beta pricing fomulas. It is shown that the...