Cross-asset derivative securities are studied and a dichotomous asset pricing model (DAPM) is derived that signi…cantly enriches the Sharpe-Lintner-Black capitalasset pricing model. An asset’s beta is shown to be observable ex ante through the price of its cross-market call or put, and the DAPM separately predicts the assets’ expected return - beta relations under the upper-market and lower-market conditions. A su¢cient condition for the DAPM to hold is that assets’ return distributions satisfy Ross’ (1978) two-fund separation property, which implies that any well-diversi…ed portfolio is both mean-variance and gain-loss e¢cient.