The Many Facets of Stock Momentum: Distinguishing Factor and Stock Components

Key Takeaways

• Earnings-announcement momentum predicts returns across US, Europe, Japan.
• Traditional momentum is exposed to market, value, industry factors.
• Announcement‑based strategy has lower turnover and systematic risk.
• Long‑run earnings‑announcement momentum shows no reversal, unlike classic momentum.
• Advisors can isolate the pure signal to reduce hidden factor bets.

Pulse Analysis

Momentum remains a cornerstone of quantitative investing, but its effectiveness often hinges on whether returns stem from broad factor cycles or genuine firm‑specific information. Recent academic debate has questioned the purity of classic 12‑month momentum, suggesting much of its edge derives from exposure to value, size and industry tilts. Gerard and Jehl’s study cuts through this controversy by extracting the portion of momentum that originates in the narrow windows surrounding earnings releases, revealing a distinct, stock‑specific driver that persists across major markets.

The earnings‑announcement component delivers a compelling risk‑return profile. Empirical tests over thirty years show statistically significant excess returns in the United States, Europe and Japan, even after controlling for changing factor exposures. Compared with traditional momentum, the announcement‑based strategy exhibits markedly lower systematic beta, roughly half the turnover, and a high correlation between long and short legs, indicating a purer signal. Moreover, the premium survives realistic transaction‑cost assumptions, making it viable for large‑cap, liquid equities where implementation friction is minimal.

For investment advisors, the findings translate into actionable portfolio tweaks. By decomposing momentum into factor and announcement sleeves, managers can retain the pure stock‑specific edge while hedging or scaling back the factor‑laden portion. This reduces unintended bets on market, value or industry cycles, potentially lowering drawdowns during factor regime shifts. Communicating the approach to clients emphasizes that the strategy leverages how markets digest company news, offering a transparent, evidence‑based narrative that aligns with long‑term investment goals.