This paper examines the behavior of corporate bond prices during the period surrounding the announcement of a rating change. We find some evidence of price change during the period from 18 to 7 months before the rating change is announced. We find no evidence of any reaction during the 6 months prior to the rating change. We also find little reaction, if any, during the month of the change or for 6 months after the change. This evidence contradicts the recent findings of Katz and Grier and Katz.
This paper examines the pricing of convertible bonds and preferred stocks. The optimal policies for call and conversion of these securities are determined via the criterion of dominance. The techniques underlying the Black-Scholes Option Model are used to price convertible securities as contingent claims on the firm as a whole.
This paper develops optimal portfolio choice and market equilibrium when investors behave according to a generalized lexicographic safety-first rule. We show that the mutual fund separation property holds for the optimal portfolio choice of a risk-averse safety-first investor. We also derive an explicit valuation formula for the equilibrium value of assets. The valuation formula reduces to the well-known two-parameter capital asset pricing model (CAPM) when investors approximate the tail of the portfolio distribution using Tchebychev's inequality or when the assets have normal or stable Paretian distributions. This shows the robustness of the CAPM to safety-first investors under traditional distributional assumptions. In addition, we indicate how additional information about the portfolio distribution can be incorporated to the safety-first valuation formula to obtain alternative empirically testable models.
This paper examines some implications of using an estimate of the variance in option valuation models. This procedure produces biased option values. It is shown that the magnitude of this bias is not large. The dispersion induced in the option price is more significant particularly for parameter values of practical interest. The nature and extent of this dispersion is examined by numerical examples. The paper suggests how a Bayesian approach could be used to cope with the estimation error.