This paper suggests that the pure‐play technique can be used in conjunction with the capital asset pricing model to determine the cost of equity capital for the divisions of a multidivision firm. Since the beta for a division is unobservable in the marketplace, a proxy beta derived from a publicly traded firm whose operations are as similar as possible to the division in question is used as the measure of the division's systematic risk. To provide empirical support for using the pure‐play technique, a sample of multidivision firms and pure‐play associated with each division is examined. It is shown that an appropriately weighted average of the betas of the pure‐play firms closely approximates the beta of the multidivision firm.

The existence of transaction costs explains why investors do not fully diversify their portfolios. This paper examines the implications of such limited diversification on equilibrium asset prices in the framework of the capital asset pricing model. In the pricing equation obtained here an asset's risk premium depends on a weighted average of its covariance with the market and its own variance.

The variance bounds on exchange rate movements implied by the monetary approach to exchange rate in an efficient foreign exchange market is shown to be violated by sample data. The paper also presents evidence showing that the forecast errors implied by the monetary model can be forecasted using historical data. The results are interpreted to suggest either the incompatibility of the monetary approach with sample data, or an inefficient foreign exchange market or both.

Sustained high rate of inflation has led to the creation of debt instruments with variable interest rate. The availability of these debt instruments presents management with the problem of the choice of the optimal debt portfolio. This paper deals with this problem assuming a given, and optimal, debt to equity ratio. Given expected monetary value maximization, an efficient frontier is derived in terms of the expected net income and probability of bankruptcy, where net income is defined as operating income minus debt repayment. This efficient frontier is shown to be also mean‐variance efficient. It is also shown that in most cases the optimal debt portfolio includes more than one debt instrument. In other words, the firm will avoid the policy of minimizing the expected cost of its debt repayments or the policy of minimizing the costs of bankruptcy. The optimal solution itself is affected by market variables like the relative expected cost of different debt instruments and by firm specific variables like the variability of its operating income stream, and the covariance between the operating income and the debt repayments.