We survey the recent literature on learning in financial markets. Our main theme is that many financial market phenomena that appear puzzling at first sight are easier to understand once we recognize that parameters in financial models are uncertain and subject to learning. We discuss phenomena...

We analyze how changes in government policy affect stock prices. Our general equilibrium model features uncertainty about government policy and a government whose decisions have both economic and non-economic motives. The model makes numerous empirical predictions. Stock prices should fall at...

We argue that the number of firms going public changes over time in response to time variation in market conditions. We develop a model of optimal IPO timing in which IPO waves are caused by declines in expected market return, increases in expected aggregate profitability, or increases in prior...

We develop a general equilibrium model of government policy choice in which stock prices respond to political news. The model implies that political uncertainty commands a risk premium whose magnitude is larger in weaker economic conditions. Political uncertainty reduces the value of the...

We develop a general equilibrium model of government policy choice in which stock prices respond to political news. The model implies that political uncertainty commands a risk premium whose magnitude is larger in weaker economic conditions. Political uncertainty reduces the value of the...

This is a solicited comment on the paper "Uncertainty and Valuations" by Cremers and Yan, August 2013, which is forthcoming in the Critical Finance Review. Cremers and Yan aim to provide "an additional litmus test for the uncertainty-convexity argument in Pastor and Veronesi (2003)." We...

We develop a general equilibrium model of government policy choice in which stock prices respond to political news. The model implies that political uncertainty commands a risk premium whose magnitude is larger in weaker economic conditions. Political uncertainty reduces the value of the...

Not necessarily. The fundamental value of a firm increases with uncertainty about average future profitability, and this uncertainty was unusually high in the late 1990s. We calibrate a stock valuation model that includes this uncertainty, and show that the uncertainty needed to match the...

We develop a model of stock valuation and optimal IPO timing when investment opportunities are time-varying. IPO waves in our model are caused by declines in expected returns, increases in expected profitability, or increases in prior uncertainty about average profitability. The model predicts...

Our simple model features agents heterogeneous in skill and risk aversion, incomplete financial markets, and redistributive taxation. In equilibrium, agents become entrepreneurs if their skill is sufficiently high or risk aversion sufficiently low. Under heavier taxation, entrepreneurs are more...