We empirically analyze rational investors' optimal response to asset price bubbles. We define bubbles as a sudden acceleration of price growth beyond the growth in fundamental value given by an asset pricing model. Our new bubble detection method requires only a limited time-series of historical...

We combine self-collected historical data from 1867 to 1907 with CRSP data from 1926 to 2012, to examine over 140 years of risk and return of one of the most popular mechanical trading strategies—momentum. We find that the momentum strategy has earned abnormally high risk-adjusted returns—a...

This paper identifies a limit to arbitrage that arises because firm value is endogenous to the exploitation of arbitrage. Trading on private information reveals this information to managers and improves their real decisions, enhancing fundamental value. While this feedback effect increases the...

Trading by commodity index traders (CITs) has become an important aspect of financial markets over the past 10 years. We develop an equilibrium model of trader behavior that relates uninformed CIT trading to futures prices. A key implication of the model is that CIT trading reduces the cost of...

Measuring individual investors' speculative demand for stocks using the Google search volume index (hereafter “SVI”) on penny stocks, we examine how it relates to the return dynamics of U.S. stock indices. Speculative demand leads to a short-term return reversal. A simple trading strategy...