Knowledge that Transforms

Abstract The paper analyzes the effect of transaction costs on social learning in an asset market with asymmetric information, sequential trading, and a competitive price mechanism. Both fixed and proportional transaction costs reduce the information content of trading orders and lead to informational cascades. If transaction costs are very high, an informational cascade may occur not only when beliefs converge on a specific asset value but also when there is extreme uncertainty about the asset's fundamental value. Finally, if the value in the bad state is sufficiently low, proportional transaction costs lead to an informational cascade only when prices are very high.

Abstract We empirically study the economic benefits of giving investors access to index options in the standard portfolio problem, analyzing both expected-utility and nonexpected-utility investors in order to understand who optimally buys and sells options. Using data on S&P 500 index options, CRRA investors find it always optimal to short out-of-the-money puts and at-the-money straddles. The option positions are economically and statistically significant and robust to corrections for transaction costs, margin requirements, and Peso problems. Loss-averse and disappointment-averse investors also optimally hold short option positions. Only with highly distorted probability assessments can we obtain positive portfolio weights for puts (cumulative prospect theory and anticipated utility) and straddles (anticipated utility).

Abstract We derive equilibrium restrictions on the range of the transaction prices of American options on the stock market index and index futures. Trading over the lifetime of the options is accounted for, in contrast to earlier single-period results. The bounds on the reservation purchase price of American puts and the reservation write price of American calls are tight. We allow the market to be incomplete and imperfect due to the presence of proportional transaction costs in trading the underlying security and due to bid-ask spreads in option prices. The bounds may be derived for any given probability distribution of the return of the underlying security and admit price jumps and stochastic volatility. We assume that at least some of the traders maximize a time- separable utility function. The bounds are derived by applying the weak notion of stochastic dominance and are independent of a trader's particular utility function and initial portfolio position.