In efficient markets the price should reflect the arrival of private information. The mechanism by which this is accomplished is arbitrage. A privately informed trader will engage in costly arbitrage, that is, trade on his knowledge that the price of an asset is different from the fundamental...

The dynamic behavior of security prices is studied in a setting where two agents trade strategically and learn from market prices. Each trader receives a private signal about fundamentals, the significance of which depends on the signal received by the other trader. In trading, each agent wants...

We consider a model of the stock market with delegated portfolio management. All agents are rational: some trade for hedging reasons, some investors optimally contract with portfolio managers who may have stock-picking abilities, and portfolio managers trade optimally given the incentives...

The dynamic behavior of security prices is studied in a setting where two agents trade strategically and learn from market prices. Each trader receives a private signal about fundamentals, the significance of which depends on the signal received by the other trader. In trading, each agent wants...