This paper examines the optimality of an insurance strategy in which an investor buys a risky asset and a put on that asset. The put's striking price serves as the insurance level. In complete markets, it is highly unlikely that an investor would utilize such a strategy. However, in some types of less complete markets, an investor may wish to purchase a put on the risky asset. Given only a risky asset, a put, and noncontinuous trading, an investor would purchase a put as a way of introducing a risk‐free asset into the portfolio. If, in addition, there is a risk‐free asset and the investor's utility function displays constant proportional risk‐aversion, then the investor would buy the risk‐free asset directly and not buy a put. In sum, only under the most incomplete markets would an investor find an insurance strategy optimal.

This study examines whether the information implied by simultaneous levels of option and stock prices (specifically, the implied standard deviation of returns) reflects other contemporaneously available information. The independent contemporaneous measure considered is the observed dispersion (across several financial analysts), at a point in time, in the forecasts of earnings per share for a given firm. The results indicate that implied standard deviations clearly reflect the contemporaneous dispersion in analysts' forecasts incrementally , i.e., beyond the information contained in the historical time series of returns.

This paper presents tests designed to determine whether the weekly pattern in stock returns continues after the introduction of futures trading on stock indexes and whether the pattern carries over to the futures market. Using data for the SP500, I find that the “Monday effect” does persist in the cash market, but there is no evidence of a similar pattern in the futures market.

This paper provides new tests of the arbitrage pricing theory (APT). Test results appear to be extremely sensitive to the number of securities used in the two stages of the tests of the APT model. New tests also indicate that unique risk is fully as important as common risk. While these tests have serious limitations, they are inconsistent with the APT.

Lease cancellation insurance protects the lessor against early termination of a cancellable operating lease. This paper presents a contingent claims model for determining the “fair” premium for this type of insurance policy. Comparative statics are considered, and some numerical examples are presented to illustrate the model. Among other things, the insurance premium is sensitive to the expected rate of economic depreciation of the leased asset and to the leased asset's systematic and nonsystematic risk.

This paper provides some new insights about approximate factor structures, as defined by Chamberlain and Rothschild [2], and their implications for empirical tests. First, we show that any economy that satisfies an approximate factor structure can be transformed, in a manner that does not alter the characteristics of investor portfolios, into an economy that satisfies an exact factor structure, as defined by Ross [9]. Second, we show that principal components analysis represents just one of many methods of forming groups of well‐diversified portfolios with no idiosyncratic risk in large samples. Correct factor loadings will be obtained by regressing security returns on any group of these portfolios. Our interpretations of the Chamberlain and Rothschild results also provide additional insights into the testability of the Arbitrage Pricing Theory. We show that securities cannot be repackaged to hide factors in the manner suggested by Shanken [10] without the variance of some of the repackaged securities approaching infinity in large economies.

This paper derives the equilibrium time series processes characterizing the prices of bonds which differ by maturity using the CAPM relationship between expected returns. The assumption of rational expectations requires that asset demand behavior, which determines bond prices in equilibrium, be based on the covariances among returns that are implied by the assumption of market clearing. This requirement imposes nonlinear restrictions on the parameters in the solution for bond prices. Some implications for the types of comparative static exercises for which it is legitimate to assume invariant demand functions are discussed, and some numerical solutions for bond prices are derived.

This paper models an individual's trading decision, given: (1) his/her demand function to hold shares of an asset, (2) his/her expectation on what the market clearing price will be, and (3) the design of the market which determines how orders will be translated into trades. The particular market design we consider is the batched trading (periodic call) regime. Assuming investors are distributed according to their propensities to hold shares, we model the aggregation of orders to obtain market clearing values of price and volume and to show the way in which, with trading friction, these solutions differ from Pareto efficient values. The importance of this analysis for various issues concerning market design is noted.