We investigate infinitely repeated games with imperfect private monitoring. We focus on a class of games where the payoff functions are additively separable and the signal for monitoring a player's action does not depend on the other player's action. Tit-for-tat strategies function very well in...

We model the stock market as a timing game, in which arbitrageurs who are not expected to be certainly rational compete over profit by bursting the bubble caused by investors' euphoria. The manager raises money by issuing shares and the arbitrageurs use leverage. If leverage is weakly regulated,...

We investigate the moral hazard problem in which a principal delegates multiple tasks to multiple workers. The principal imperfectly monitors their action choices by observing the public signals that are correlated with each other through a macro shock. He divides the workers into two groups and...

We investigate the adverse selection problem where a principal delegates multiple tasks to individuals. The individuals form a group as a single agent and share their private signals in order to maximize their average payoff. We characterize the virtually implementable social choice functions by...

We analyze the stock market by modeling it as a timing game among arbitrageurs for beating the gun. We assume that (1) arbitrageurs are behavioral with a small probability, (2) the bubble soft-lands, and (3) the postcrash price increases as the X-day is postponed. Due to these assumptions, the...

We investigate implementation in the complete information environments, where a social choice function is defined as a mapping from states to lotteries, and there exist four or more agents. We assume that for every agent, any pair of distinct states induces distinct strict preference orderings...

This paper investigates unique implementation in large economies with incomplete information and interdependent values; we degenerate the common knowledge assumptions and assume that a central planner is unaware of the specifications of an environment. With a minor restriction on the class of...