Modern investors face a high-dimensional prediction problem: thousands of observable variables are potentially relevant for forecasting. We reassess the conventional wisdom on market efficiency in light of this fact. In our model economy, which resembles a typical machine learning setting, N...

From 1973 to 2014, the common stock of U.S. banks with loan growth in the top quartile of banks over a three-year period significantly underperforms the common stock of banks with loan growth in the bottom quartile over the next three years. The benchmark-adjusted cumulative difference in...