The 2008 financial crisis raised puzzles important for understanding how the capital market prices common stocks and in turn, for the intersection between law and finance. During the crisis, there was a dramatic fivefold spike, across all industries, in idiosyncratic risk – the volatility of individual-firm share prices after adjustment for movements in the market as a whole. This phenomenon is not limited to the most recent financial crisis.This Article uses an empirical review to show that a dramatic spike in idiosyncratic risk has occurred with every major downturn from the 1920s through the recent financial crisis. It canvasses three possible explanations for this phenomenon. Thereafter, this Article explores the implications of these...