Momentum is one of the best-documented phenomena in financial markets: Stocks that have risen over the past 3-12 months tend to continue rising. And vice versa. Since discovery by Jegadeesh and Titman (1993), the effect has been confirmed in dozens of studies — across all markets and time periods.

Why Does Momentum Work?

Underreaction: Investors react too slowly to new information. Good news is gradually priced in, not immediately.
Herding behavior: When a stock rises, it attracts more buyers. Media attention, analyst upgrades, and social media hype amplify the trend.
Disposition effect: Investors sell winners too early and hold losers too long — this slows uptrends and extends downtrends.

Measuring Momentum

Absolute Momentum

Compares a stock with itself: Is the price higher than 6 or 12 months ago? If yes, buy. If no, avoid or short.

Relative Momentum

Compares stocks against each other: Which top 10-20% of stocks in a universe have the best performance over the last 3-12 months? These are bought.

Dual Momentum (Gary Antonacci)

Combines both: First check if an asset class has positive absolute momentum (rising). Then select the relatively strongest within positive classes. Simple, rule-based, historically very successful.

Momentum + AI: The Synergy

Momentum alone is a simple rule. AI enhances it through:

Multi-factor momentum: Not just price momentum, but also earnings momentum, analyst revision momentum, and sentiment momentum
Crash filter: AI recognizes when momentum stocks are overheated and shuts down the system before a momentum crash
Sector momentum: Automatically rotates into sectors with strongest momentum

Risks of the Momentum Strategy

Momentum crash: When trends suddenly reverse (2009, 2020), momentum portfolios lose disproportionately
High turnover: Momentum requires regular rebalancing — transaction costs and taxes eat returns
Late-cycle risk: At the end of a bull market, momentum often concentrates in a few expensive stocks

Practical Implementation

ETF solution: iShares MSCI World Momentum Factor ETF — 0.30% TER, automatically the 300+ strongest momentum stocks worldwide
Individual stocks: Monthly screen top-20 momentum stocks in S&P 500 or DAX based on 6-month performance
AI signal-based: Use Dieter signals with momentum filter — only trade signals that align with positive momentum

Bottom Line: Momentum is not hype — it is one of the most reliable factors in financial market research. Combined with AI signals and risk management, it is one of the strongest strategies for active traders.