Knowledge that Transforms

Speculative bubbles have been offered to explain the excess volatility results by Shiller (1981) and LeRoy and Porter (1981). Recent work by Flood, Hodrick, and Kaplan has shown that rational speculative bubbles cannot be the explanation for the excess volatility results. This paper provides an analytical framework for examining the hypothesis that the simple present value model used for the excess volatility studies is a misspecification of the true model. The method is applied to data from a market index and four large corporations. The results are consistent with the hypothesis that the simple present value model is not the correct specification for stock market pricing.

What happens to the price of a put in a period during which the stock price stays constant? The hedging strategy implicit in the Black-Scholes model would seem to imply that the put goes up in value. Pure arbitrage arguments imply the opposite result. This paper resolves the paradox and uses it to explore the restrictions inherent in the diffusion processes assumed for all option pricing models.

Livingston contends that short futures/long cash traders can eliminate the potential costs of the quality option through use of a dynamic trading strategy. It is proposed here that if this is possible then futures prices will never reach a stable equilibrium. Alternatively, if Livingston's argument is flawed, then no risk-free arbitrage opportunities are likely to be available to either short cash/long futures or long cash/short futures traders. Under such conditions, futures prices will reach an equilibrium when the expected return and risk of each type position are equally attractive.

In a perfectly efficient market, after adjusting for drift, futures prices would follow a martingale model. The martingale property implies that the changes in futures prices should be serially uncorrelated. This study finds that the price changes of the S&P 500 futures contracts during 1983 and 1984 have negative serial correlation and are better described by a random walk model with reflecting barriers or by a random walk model with reflecting barriers and mean reversion.

This study is an ex post performance test comparing the accuracy of an American model to a European model for valuing listed options. Specifically, the Geske and Johnson American put valuation model is compared with the Black and Scholes European put model. On average, both models undervalue, relative to market prices, put options. However, the Geske and Johnson model values are significantly closer to market prices than are the Black and Scholes values.

This research provides improved techniques for analyzing the after-tax risk exposure of taxable institutions holding amortizing instruments such as commercial, real estate, and consumer loans. We derive after-tax duration for amortizing instruments and analyze it for sensitivity to tax rates, coupon, and maturity. Taxable investors who hedge and ignore the effects of taxes on amortizing instruments will underestimate differences in durations on bonds versus amortizing instruments of equal maturities; bond durations increase much faster as tax rates increase. One unexpected result shows that, unlike bond duration, amortizing instrument duration often increases with coupon rate, and sometimes is independent of coupon rate.

Previous investigators have shown that the Sharpe measure of the performance of a managed portfolio may be flawed when the portfolio manager has market timing ability. Herein we develop the exact conditions under which the Sharpe measure will completely and correctly order market timers according to ability. The derived conditions are necessary, sufficient, and observable. We compare these derived conditions to empirical estimates of actual market conditions and find that, under typical market conditions, the practice of using quarterly portfolio return data will frequently result in a failure of the Sharpe measure to order timers according to ability. We show, however, that such failures can be greatly reduced by more frequent sampling of managed portfolio returns.

Joseph P. Ogden, Alan L. Tucker, The Relative Valuation of American Currency Spot and Futures Options: Theory and Empirical Tests, The Journal of Financial and Quantitative Analysis, Vol. 23, No. 4 (Dec., 1988), pp. 351-368

A number of futures contracts conveys to the short position various delivery options regarding the quality and exact timing of delivery. Moreover, the compensation to the long position is not solely determined by the market value of the delivered asset at the time of delivery. Sometimes, the long position can hedge this delivery risk by holding an appropriate portfolio of the underlying asset. It often has been stated that whenever the long position can form a dynamic hedge against the delivery risk, the delivery option has a zero value. This paper demonstrates the implication of such erroneous intuition to the pricing of options. It is shown that the root of the issue is the property of diffusion processes whereas, within a given time interval, a random variable either will never cross a given boundary or else, cross it an infinite number of times.

This paper shows how a derivative security can be duplicated by a forward strategy, and, hence, priced by arbitrage in terms of the forward price.