This paper presents a simple general equilibrium model of asset pricing in which profitable informed trading can occur without any "noise" added to the model. It shows that models of profitable informed trading must restrict the portfolio choices of uninformed traders: in particular, they cannot...

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...