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...

We present a model of incomplete information games with sets of priors. Upon arrival of private information, each player "updates" by the Bayes rule each of priors in this set to construct the set of posteriors consistent with the arrived piece of information. Then the player uses a possibly...

This paper considers a two agent model of trade with multiple priors. First, we characterize the existence of an agreeable bet on some event in terms of the set of priors. It is then shown that the existence of an agreeable bet on some event is a strictly stronger condition than the existence of...

A game in which an incumbent and an entrant decide the timings of entries into a new market is investigated. The profit flows involve two uncertain factors: (1) the basic level of the demand of the market observed only by the incumbent and (2) the fluctuation of the profit flow described by a...

The purpose of this paper is twofold. First, we generalize Kajii et al. (2007), and provide a condition under which for a game v, its Mobius inversion is equal to zero within the framework of the k-modularity of v for k = 2. This condition is more general than that in Kajii et al. (2007)....

In this paper, we study an investment problem in which two asymmetric firms face competition and the regime characterizing economic conditions follows Markov switching. We derive the value functions and investment thresholds of a leader and a follower. One of the interesting results is that in...

Extending the Grossman [12] model of health capital into a stochastic one, we analyze how the presence of Knightian uncertainty about the efficacy of health care affects the optimal health investment behavior of individuals. Using Gilboa and Schmeidler's [11] model of maxmin expected utility...

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...