Discounting timing strategies

A variety of timing strategies shown to generate alpha and high Sharpe ratios at the monthly horizon exhibit substantially deteriorated performance at longer investment horizons. The effect is large: multi-factor alphas are more than halved going from one-month to 10-year returns, and factors that exploit time-series predictability drive them to zero. I argue that such return dynamics reflect compensation for exposure to shocks that are particularly risky from a long-horizon investor’s perspective. I illustrate the idea by showing that seasonality in the volatility of price-of-risk and expected-cash-flow shocks generates seemingly profitable timing strategies.