In a model of asset markets with transaction costs, we find a sufcient condition for an increase in transaction costs to increase buying prices, decrease selling prices, decrease the trading volume, and make all active investors worse off. The sufficient condition is met by all CARA utility...

In an exchange economy in which there is a complete set of markets for macroeconomic risks but no market for idiosyncratic risks, we consider how the efficient risk-sharing rules for the macroeconomic risk are affected by the heterogeneity in the consumers' risk attitudes and idiosyncratic...

In a continuous-time economy with complete markets, we study how the heterogeneity in the individual consumers' risk tolerance and impatience affects the representative consumer's risk tolerance and impatience. We derive some formulas, which indicate that the representative consumer's impatience...

We provide necessary and sufficient conditions on an individual's expected utility function under which any zero-mean idiosyncratic risk increases cautiousness (the derivative of the reciprocal of the absolute risk aversion), which is the key determinant for this individual's demand for options...

In an exchange economy under uncertainty populated by consumers having constant and equal relative risk aversion but heterogeneous probabilistic beliefs, we analyze the nature of the representative consumer's probabilistic belief and discount rates. We prove a formula that implies that the...

Following LeRoy and Werner (2001), we propose a definition of effectively complete asset markets in a model with multiple goods and multiple periods, and establish the first and second welfare theorems in such markets. As applications of the first welfare theorem, we derive the sunspot...

A univariate real-valued function is said to be completely monotone if it takes positive values and alternate the signs of its higher order derivatives, starting from everywhere negative first derivatives. We prove that the representative consumer's discount factor of a continuous-time economy...

We prove that every continuous-time model in which all consumers have time-homogeneous and time-additive utility functions and share a common probabilistic belief and a common discount rate can be reduced to a static model. This result allows us to extend some of the existing results on the...

In an exchange economy under uncertainty with two periods, one physical good, and finitely many states of the world, we show that for every (complete or incomplete) market span there exists a sequence of securities such that if they are introduced into markets one by one, the prices of any...

We study the optimal portfolio choice problem of an investor who is averse to both risk and ambiguity. Using the class of utility functions proposed by Klibano, Marinacci, and Mukerji (2005), we establish a generalized mutual fund theorem, which shows that there are a xed number of mutual funds...