The Welfare Costs of the Australian Telecommunications Pricing Structure*

Australian telecommunications pricing has developed in an environment which is uncompetitive, subject to pressures to cross-subsidize and insufficiently cognizant of relevant costs and demands. STD and local call charges are too high and access charges too low. Compared with a structure which charged marginal usage costs and retrieved costs of subscribers' loops and overheads through access charges, the pricing structure has an estimated efficiency cost of about $240 m in 1985–86.     

Incentives and Standards in Agency Contracts

This paper studies the structure of state‐contingent contracts in the presence of moral hazard and multitasking. Necessary and sufficient conditions for the presence of multitasking to lead to fixed payments instead of incentive schemes are identified. It is shown that the primary determinant of whether multitasking leads to higher or lower powered incentives is the role that noncontractible outputs play in helping the agent deal with the production risk associated with the observable and contractible outputs. When the noncontractible outputs are risk substitutes and are socially undesirable, standards are never optimal. If the noncontractible outputs are socially desirable, standards are never optimal if the noncontractible outputs play a risk‐complementary role.     

An Empirical Analysis of the Role of the Medium of Exchange in Mergers

In empirical studies of differences between firms which are acquired and those which are not, researchers typically divide firms into two groups-acquired and nonacquired. In this paper, we argue that cash takeovers may be sufficiently different from noncash acquisitionst hat failure to distinguish between them may lead to inappropriateg eneralizations. We provide evidence from the mid 1970s that three categories of firms can be distinguished:n onacquireda, cquiredi n a cash takeover, and acquired in an exchange of securities.     

Mimicking Portfolios and Exact Arbitrage Pricing

We characterize the sets of mimicking positions with returns that can serve in place of factors in an exact K-factor arbitrage-pricing relation for a set of N assets. All of the sets are K-dimensional nonsingular linear transformations of each other. We interpret three examples of such transformations and discuss empirical considerations. We provide conditions under which the mimicking positions can be expressed as portfolios, and we characterize the relation between mimicking portfolios and the minimum-variance frontier.     

The Size and Incidence of the Losses from Noise Trading

Recent empirical research has identified a significant amount of volatility in stock prices that cannot easily be explained by changes in fundamentals; one interpretation is that asset prices respond not only to news but also to irrational “noise trading.” We assess the welfare effects and incidence of such noice trading using an overlapping-generations model that gives investors short horizons. We find that the additional risk generated by noise trading can reduce the capital stock and consumption of the economy, and we show that part of that cost may be borne by rational investors. We conclude that the welfare costs of noise trading may be large if the magnitude of noise in aggregate stock prices is as large as suggested by some of the recent empirical litrature on the excess volatility of the market.     

Arbitrage,Continuous Trading,and Margin Requirements

This paper studies the impact that margin requirements have on both the existence of arbitrage opportunities and the valuation of call options. In the context of the Black-Scholes economy, margin restrictions are shown to exclude continuous-trading arbitrage opportunities and, with two additional hypotheses, still to allow the Black-Scholes call model to apply. The Black-Scholes economy consists of a continuously traded stock with a price process that follows a geometric Brownian motion and a continuously traded bond with a price process that is deterministic.