Investing | August 20, 2026 | Capstag.com | 11 min read
Momentum Investing: What It Is and Whether It Actually Works
Momentum investing sounds like the opposite of disciplined, long-term investing — simply buying what has recently risen and selling what has fallen. Yet it is one of the most thoroughly documented and empirically robust strategies in all of finance, backed by research spanning more than 150 years of market data. Understanding what it actually is, why the evidence supports it, and what its real limitations are is worth any investor's time.
Quick Answer: Momentum investing is a strategy that systematically buys stocks with the strongest recent price performance — typically ranked on the past 6 to 12 months of returns — and avoids or short-sells the weakest performers, based on the documented tendency for recent winners to continue outperforming and recent losers to continue underperforming over a short to medium-term horizon. According to research published in the Journal of Portfolio Management in 2026 by Baltussen et al., momentum demonstrates robust empirical support across domestic and global stock markets spanning up to 150 years of data. Its primary limitation is crash risk — sharp, sudden reversals during market regime shifts that can produce severe short-term losses.
Of all the strategies in quantitative finance, momentum is perhaps the most counterintuitive. Classical finance theory holds that past price performance contains no information about future returns — that markets are efficient enough to price everything known already. Momentum directly challenges that assumption, and the evidence supporting it is strong enough that it cannot be dismissed. According to Morningstar's analysis, momentum runs counter to the predictions of the efficient market hypothesis, but the evidence is too overwhelming to ignore. What follows is a clear-eyed account of what momentum investing actually is, what the data shows, and how a long-term individual investor should think about incorporating it or avoiding it in their portfolio.
What Is Momentum Investing?
Momentum investing is a strategy that ranks securities based on their past price performance over a defined lookback period — typically six to twelve months — and systematically invests in the top performers (winners) while avoiding or underweighting the bottom performers (losers). The underlying premise is that stocks which have outperformed recently tend to continue outperforming over the near to medium term, and stocks that have underperformed tend to continue underperforming over the same horizon.
This is distinct from trend following, though related. Trend following typically applies to asset classes (commodities, currencies, bonds, broad equity markets) over longer time horizons. Momentum in equity markets specifically refers to the cross-sectional ranking of individual stocks relative to each other — identifying which stocks within a universe have the strongest recent performance relative to their peers, and tilting toward those names.
The Academic Foundation: Where the Evidence Comes From
The academic case for momentum begins with Jegadeesh and Titman's landmark 1993 paper "Returns to Buying Winners and Selling Losers," published in the Journal of Finance. Analysing US stock data from 1965 to 1989, they found that stocks with the best performance over the past 3 to 12 months continued to outperform the worst-performing stocks over the following year. Critically, subsequent research confirmed the effect was present in the US before and after this original sample period — ruling out the possibility that it was simply an artefact of the specific data range studied.
The evidence has expanded dramatically since 1993. According to research published by Baltussen, Dom, Van Vliet and Vidojevic in a forthcoming 2026 paper in the Journal of Portfolio Management, momentum demonstrates robust empirical support for the momentum factor across domestic and global stock markets spanning up to 150 years of data and a wide variety of design choices, establishing momentum's resilience against data mining and arbitrage concerns. According to the CFA Institute's December 2025 analysis of this research, the study draws on more than 150 years of data and thousands of portfolio specifications, reaffirming momentum's resilience across time periods, geographies, and construction methods.
According to London Business School researchers Elroy Dimson, Paul Marsh and Mike Staunton, who analysed stock price history starting from 1900, a strategy of systematically investing in top-performing stocks over a rolling lookback period produced returns that would be considered remarkable if viewed in isolation — confirming the phenomenon is not a short-term statistical artefact but a structural feature of equity markets across multiple market regimes and a full century of economic history.
Why Momentum Works: The Behavioural Explanation: The most widely accepted explanation for momentum's persistence is behavioural rather than structural. Markets do not immediately incorporate all new information into prices — investor psychology creates predictable delays. Underreaction to good news causes winners to continue rising as the full positive implication of the information is gradually priced in. Herding behaviour and recency bias cause investors to chase recent winners, providing further price momentum beyond the fundamental signal. According to IBKR Campus's January 2026 analysis, momentum works not because markets are inefficient in a trivial sense but because human behaviour is slow to adjust — price trends persist longer than classical financial theory predicts.
How Momentum Is Measured: The 6–12 Month Signal
The most commonly used momentum signal measures a stock's total return over the past twelve months excluding the most recent month — written as "12-1 momentum" or "12-month minus 1-month." The exclusion of the most recent month is designed to avoid a short-term reversal effect where stocks that jump sharply in one month tend to pull back slightly the following month. Research has consistently shown that the 6 to 12-month lookback window captures the momentum effect most reliably, while shorter windows (one month) capture a reversal effect and longer windows (3 to 5 years) show a different, value-like mean reversion effect.
In practice, a momentum screen ranks all stocks in a universe by their 12-1 month return, then selects the top decile or quintile (top 10% or 20%) as the "winner" portfolio. The strategy holds these winners for a period — typically one to three months — before re-ranking and reconstituting the portfolio. The higher the turnover required to maintain a momentum portfolio, the greater the transaction cost drag, which is one reason momentum is often used in longer rebalancing cycles to reduce trading costs.
Momentum in Practice: Factor ETFs and Indices
Individual investors do not need to build a momentum portfolio from scratch. Several ETFs specifically target the momentum factor, providing systematic exposure without the turnover and transaction cost burden of implementing the strategy manually.
| ETF | Ticker | Index | Expense Ratio |
|---|---|---|---|
| iShares MSCI USA Momentum Factor ETF | MTUM | MSCI USA Momentum Index | 0.15% |
| Invesco S&P 500 Momentum ETF | SPMO | S&P 500 Momentum Index | 0.13% |
| Alpha Architect US Quantitative Momentum ETF | QMOM | US Quantitative Momentum Index | 0.49% |
According to data cited by IBKR Campus's January 2026 analysis of momentum strategy performance, across all medium- and long-term horizons measured, the S&P 500 Momentum Index clearly outperformed the traditional S&P 500 over 10-year and 20-year periods, though with higher volatility. Over 10-year horizons, momentum strategies historically generated substantially higher total performance than the benchmark, albeit with periods of significant underperformance that require discipline to hold through.
The Real Limitation of Momentum: Crash Risk
Momentum's most significant weakness is its crash risk — the tendency for momentum portfolios to experience sharp, sudden, severe drawdowns during market regime shifts. According to the CFA Institute's analysis of the Baltussen et al. 2026 research, momentum is exposed to crash risk, with sharp reversals particularly during market regime shifts representing the Achilles heel of the strategy.
The mechanism behind momentum crashes is straightforward. When a market regime shifts — from bull to bear, or from one sector leadership theme to another — momentum portfolios are by definition positioned in the previous regime's winners. If technology stocks have led the market for two years and momentum portfolios are therefore heavily weighted in technology, a sudden rotation toward defensive stocks will hit a momentum portfolio on both sides simultaneously: the held positions (former winners) decline, while the exited positions (former losers) advance.
The 2009 Momentum Crash: The most severe modern example of momentum crash risk occurred in the first half of 2009, following the financial crisis. After a prolonged period of losses across most sectors, momentum portfolios were positioned heavily in the few sectors that had "won" during the downturn — defensive and short positions in the hardest-hit cyclical stocks. When the market began its recovery in March 2009, the reversal was sharp and concentrated in exactly the areas momentum portfolios had avoided or shorted. The resulting losses in momentum strategies during this single reversal period temporarily overwhelmed years of accumulated outperformance for investors who had not anticipated the regime shift. Risk-managed momentum strategies — which reduce position size when portfolio volatility spikes — have since been developed specifically to address this crash risk.
Momentum vs Other Investing Strategies
| Factor | Momentum | Value | Quality | Low Volatility |
|---|---|---|---|---|
| Core Signal | Recent price performance | Low valuation ratios | High profitability/ROE | Low price volatility |
| Academic Support | Very strong | Very strong | Strong | Strong |
| Turnover Required | High | Low to Medium | Low | Low |
| Crash Risk | High | Medium | Low | Low |
| Best Environment | Trending markets | Recovery periods | Any | High-volatility periods |
One of the most interesting findings in factor investing research is that momentum and value tend to be negatively correlated — when one performs strongly, the other often underperforms. This makes their combination more powerful in a blended factor portfolio than either alone, since the negative correlation between them provides a natural diversification benefit that reduces the severity of drawdown in any single period. According to the CFA Institute's analysis of the 2026 research, the combination of price momentum with ten alternative momentum signals (earnings momentum, revenue momentum, and others) in a multidimensional composite produced superior returns and risk-adjusted performance relative to price momentum alone.
Should Individual Investors Use Momentum Investing?
For most individual long-term investors, direct implementation of a momentum strategy — manually ranking stocks by past performance and rotating regularly — is impractical due to the high turnover required, the transaction costs that erode the strategy's edge, and the emotional difficulty of holding through sharp reversal periods when the strategy's positions have just declined significantly.
The more practical approaches for individual investors are through a momentum factor ETF (MTUM or SPMO), which provides systematic exposure without manual implementation, or by incorporating momentum as one consideration among several in a broader fundamental analysis process — using price momentum as a confirming signal rather than the primary investment criterion.
From a Risk Management Perspective: The most compelling argument for individual investors to understand momentum investing is not that they should implement a pure momentum strategy themselves, but that it explains an observable market phenomenon that affects every investor. Understanding that recent winners tend to continue winning in the near term — and that regime shifts can cause violent reversals — helps investors interpret their own holdings' price behaviour more accurately, resist the temptation to sell recent winners too early based on valuation alone, and avoid doubling down on recent losers simply because they have fallen without asking whether the trend has genuinely reversed or merely accelerated.
Conclusion
Momentum investing is one of the most thoroughly documented phenomena in financial research — supported by more than 150 years of data across multiple geographies, validated against data mining concerns, and confirmed to persist despite widespread institutional awareness. The behavioural explanation — that markets underreact to new information and that human psychology creates predictable price trend persistence — is compelling and well-supported by empirical evidence. The strategy's primary limitation is equally well-documented: crash risk during regime shifts that can produce concentrated losses requiring genuine patience to recover from. For individual investors, the most practical application is either through a low-cost momentum factor ETF or as a secondary confirming signal in a broader research process — not as a standalone primary strategy requiring manual stock rotation. For more on how factor investing fits into the broader universe of strategies, see our guide on Growth Investing vs Value Investing: Which Strategy Works Better?
✅ Key Takeaways
- Momentum investing systematically buys recent top-performing stocks and avoids recent underperformers, based on the documented tendency for performance to persist over 6–12 month horizons
- According to research by Baltussen et al. published in the Journal of Portfolio Management in 2026, momentum demonstrates robust empirical support across domestic and global markets spanning up to 150 years of data
- The foundational 1993 paper by Jegadeesh and Titman first documented the momentum effect in US stocks from 1965–1989; subsequent research confirmed the effect across geographies, time periods, and construction methods
- The most widely accepted explanation is behavioural — investor underreaction to information and herding cause price trends to persist longer than efficient market theory predicts
- The standard momentum signal uses 12-month minus 1-month returns — the most recent month is excluded to avoid the short-term reversal effect
- Crash risk is momentum's primary weakness — sharp reversals during market regime shifts can produce severe short-term losses that overwhelm accumulated gains
- Momentum and value factors are negatively correlated — combining them in a portfolio reduces drawdown severity compared to using either factor alone
- For most individual investors, the practical approach is a momentum factor ETF (MTUM, SPMO) rather than manual stock rotation — momentum's high turnover makes direct implementation costly
Frequently Asked Questions
What is momentum investing in simple terms?
Momentum investing is the strategy of buying stocks that have performed best over the recent past — typically ranked over a 6 to 12-month window — based on the documented tendency for recent winners to continue outperforming and recent losers to continue underperforming over a short to medium-term horizon. It does not involve analysis of company fundamentals, valuation, or earnings — only past price performance relative to other stocks in the same universe.
Does momentum investing actually work?
Yes, based on the research evidence. According to Baltussen et al.'s 2026 paper in the Journal of Portfolio Management, momentum demonstrates robust empirical support across domestic and global stock markets spanning up to 150 years of data. The S&P 500 Momentum Index has outperformed the standard S&P 500 over 10-year and 20-year horizons, according to IBKR Campus's January 2026 analysis. However, it carries significant crash risk during market regime shifts and requires discipline to hold through periods of sharp underperformance.
What is momentum factor investing?
Momentum factor investing is the systematic application of the momentum signal — ranking securities by past price performance and overweighting recent winners — as a deliberate portfolio construction strategy, typically implemented through a rules-based index or ETF. Factor investing uses quantitative, systematic criteria to build portfolios rather than qualitative analysis of individual companies. The momentum factor is one of five commonly studied equity factors alongside value, quality, low volatility, and size.
What is the biggest risk of momentum investing?
The biggest risk is crash risk — the tendency for momentum portfolios to experience sharp, sudden, severe losses during market regime shifts. When market leadership rotates from the assets momentum portfolios hold to the assets they have avoided, the resulting reversal hits the portfolio on both sides simultaneously. The 2009 recovery following the financial crisis produced one of the most severe momentum crashes in modern market history, temporarily overwhelming years of accumulated outperformance for undiversified momentum investors.
How is momentum investing different from trend following?
Momentum investing in equities is a cross-sectional strategy — it ranks stocks relative to each other and invests in whichever have performed best over a recent period, regardless of whether the overall market is rising or falling. Trend following is typically a time-series strategy — it asks whether a specific asset is trending up or down compared to its own history, and takes long or short positions accordingly. Both strategies exploit the persistence of price trends but do so at different levels: stocks versus each other (momentum) versus an asset versus its own past (trend following).
Can beginners use momentum investing?
Direct momentum investing — manually ranking stocks and rotating regularly — is not practical for most beginners due to the high turnover required, the transaction costs that erode returns, and the emotional difficulty of holding through crash-risk periods. The most accessible approach for beginners interested in momentum exposure is a momentum factor ETF such as MTUM or SPMO, which implements the strategy systematically at low cost without requiring manual stock selection or frequent trading.
This article is for educational purposes only. The information provided reflects general financial principles and does not constitute personalised financial, tax, or legal advice. Always consider your own financial circumstances before making any decisions.
