Asness et al. (2014): Fact, Fiction, and Momentum Investing

#Dispelling the Myths

Myth 1: Momentum Returns are Too Small and Sporadic Critics argued Momentum returns are less consistent than Value returns. **The Fact:** Asness showed that the raw return premium for Momentum is actually *larger* and *more robust* than Value. A standard Momentum factor (UMD) generates a higher Sharpe ratio than Value (HML) across almost every historical period measured.

Myth 2: Momentum Only Works in Illiquid Small Caps Critics believed Momentum was driven entirely by retail investors chasing illiquid penny stocks. **The Fact:** Momentum is incredibly strong in large-cap stocks. While the premium is slightly higher in small caps, the Momentum effect is statistically and economically massive within the S&P 500 equivalent universe. It is highly scalable.

Myth 3: Momentum is Destroyed by Trading Costs Because you are constantly buying stocks that have gone up and selling stocks that have gone down, the turnover is high. Critics argued that trading commissions and bid-ask spreads would consume all the profits. **The Fact:** By acting as a liquidity provider instead of a liquidity taker, using patience, and intelligently netting trades (e.g., crossing a momentum buy with a value sell internally), transaction costs are reduced to a fraction of a percent, leaving the massive return premium entirely intact.

#The Ultimate Symbiosis: Value + Momentum

The masterpiece conclusion of the paper details why pitting Value against Momentum is entirely foolish. Value and Momentum are intrinsically negatively correlated. - A Value stock is generally a stock that has suffered poor recent returns. - A Momentum stock is a stock that has enjoyed massive recent returns.

Because they negatively correlate, a portfolio combining 50% Value and 50% Momentum achieves a Sharpe ratio vastly superior to either factor in isolation.