Knowledge that Transforms

OLS regression ignores both heteroscedasticity and cross‐correlations of abnormal returns; therefore, tests of regression coefficients are weak and biased. A Portfolio OLS (POLS) regression accounts for correlations and ensures unbiasedness of tests, but does not improve their power. We propose Portfolio Weighted Least Squares (PWLS) and Portfolio Constant Correlation Model (PCCM) regressions to improve the power. Both utilize the heteroscedasticity of abnormal returns in estimating the coefficients; PWLS ignores the correlations, while PCCM uses intra‐and inter‐industry correlations. Simulation results show that both lead to more powerful tests of regression coefficients than POLS.

Some equilibrium prices in CAPM may be negative because of nonmonotonicity of preferences. We identify several sets of sufficient conditions for prices to be positive. The central conditions impose bounds on the investors' risk aversion. These bounds do not need to hold globally but only in a relevant range of portfolios or combinations of mean and standard deviation. The relevant range is specified on the basis of exogenous parameters and variables, and it must contain any endogenously determined equilibrium. The bounds on risk aversion ensure that the preferences for assets are sufficiently well‐behaved within the relevant range.

In this paper we develop a time consistent rational expectations model which analyzes the equilibrium loan contract between a borrowing country and a foreign bank. The loan contract specifies both the amount of the loan and the promised interest payments, and rationally reflects the investment decisions of the country and the possibilities of renegotiation and repudiation of the debt. An important feature of the model is that at the initial negotiation of the loan there is uncertainty about whether the country will renegotiate for partial forgiveness in the future, and whether it will eventually repudiate the debt, even having successfully renegotiated. Moreover, the probabilities of renegotiation and repudiation, and the amount of possible forgiveness are endogenously determined. In the model the repudiation decision is directly related to the underinvestment problem; the objective of the renegotiation is precisely to alleviate this problem. The model is used to analyze the effects of four variables on both the optimal contract and the country's welfare: the degree of penalties that a bank can impose on a defaulting country, the uncertainty of production, the productivity of investments and the riskless interest rate. The analysis has policy implications as well as testable predictions.

Studies suggest that underwriting syndicates provide marketing services and certify the fairness of offer prices. We argue that syndicate lead banks also monitor manager effort, increasing the value of capital-raising companies. A given level of monitoring is associated with a given level of intrinsic value, so there is a “schedule” of certifiable offer prices, depending on the level of monitoring. Monitoring, marketing, and certification are, therefore, all legitimate syndicate functions. New evidence supporting the conclusion that syndicates provide corporate monitoring is presented.

We study the impact of voluntary trade by the manager. We find that, in contrast to standard signaling models, an action is good news for some firms and bad news for others, depending on observable characteristics of the firm, its managers, and their compensation plans. Further, voluntary trade eliminates separating equilibria and thus the possibility of exactly inferring the manager's private information. This may cause the manager to take inefficient actions so as to earn trading profits. Such undesirable behavior can be more effectively constrained by compensation contracts based on phantom shares or nontradeable options instead of large stockholdings.