Knowledge that Transforms

This paper analyzes the market for financial assets in a production and exchange economy with several realized outputs and a single unobservable source of nondiversifiable risk. The paper demonstrates that, for a large class of diffusion outputs and preferences, optimizing consumers first estimate the realizations of the unobservable factor and then use these estimates to determine portfolio and consumption rules. Moreover, the explicit consideration of this unobservable productivity factor affects equilibrium demands and prices. The equilibrium spot rate of interest emerges as the “best estimate” of the unobservable factor, and multiperiod default-free bonds arise as the optimal hedge for the unobservable changes of the stochastic investment opportunity set.

Based on a new options transactions data base from the Philadelphia Stock Exchange Foreign Currency Options Market, this paper examines the importance of the effect of nonsynchronous prices and transaction costs on the usual option market efficiency tests. The tests conducted are based on the transaction cost adjusted early exercise and put‐call parity pricing boundaries applicable to the American foreign currency options market. The test results show that the put‐call parity boundary tests are sensitive to both nonsynchronous prices and transaction costs. The early exercise boundary tests are sensitive to transaction costs but are not very sensitive to simultaneity of the option price and the underlying spot price. Under the no‐transaction costs scenario, a large number of early exercise boundary violations is found even when simultaneous spot and option prices are used. These violations disappear when actual transaction costs are taken into account.

This paper derives a framework for arbitrage models in markets with frictions. It generalizes the existence of a valuation operator to such markets. As in perfect markets, the valuation operator is a linear operator and its existence is implied by the no‐arbitrage condition. In imperfect markets the valuation operator is individual‐specific and depends on the agent's position in the market. The methodology employed in the paper is duality in convex programming.

This paper analyzes the tax‐loss selling hypothesis as an explanation of the January seasonal in stock returns and argues that rational tax‐loss selling implies little relation between the January seasonal and the long‐term loss. Empirical results show that the January seasonal is as strongly related to the long‐term loss as it is to the short‐term loss. The evidence is inconsistent with a model that explains the January seasonal by optimal tax trading.

A lower bound on the distribution function of the likelihood ratio test of portfolio efficiency is derived. An empirical application demonstrates that the bound may sometimes be used to infer rejection of the null hypothesis without appeal to asymptotic statistical approximations. A procedure for incorporating partial information about the zero‐beta intercept, in the multivariate framework, is also developed and applied.

This paper derives a closed-form valuation model in a two-country world in which the domestic investors are constrained to own at most a fraction, δ, of the number of shares outstanding of the foreign firms. When the “δ constraint” is binding, two different prices rule in the foreign securities market, reflecting the premium offered by the domestic investors over the price under no constraints and the discount demanded by the foreign investors. The premium is shown to be a multiple of the discount, the multiple being the ratio of the aggregate risk aversion of the domestic and foreign investors. Given the aggregate risk-aversion parameters, the equilibrium premium and discount are determined by the severity of the δ constraint and the “pure” foreign market risk.

Filter rule profits found in foreign exchange markets in the early days of the current managed float persist in later periods, as shown by statistical tests developed and implemented here. The test is consistent with, but independent of, a wide variety of asset pricing models. The profits found cannot be explained by risk if risk premia are constant over time. Inclusion of the home-foreign interest rate differential in computing profits has little effect on the comparison of filter returns to those of buy-and-hold.