What Are Momentum Funds?

There is an idea in investing that feels counterintuitive the first time you encounter it: stocks that have been going up recently tend, on average, to keep going up for a while longer, and stocks that have been falling tend to keep falling.

This is not a trading tip or a piece of market gossip. It is one of the most robustly documented patterns in financial research, studied across markets, asset classes, and decades of data. It is called the momentum effect, and momentum funds are designed to systematically capture it.

In India, momentum mutual funds have moved from being a niche academic curiosity to a category with several fund offerings, index products, and a growing body of investor interest. Understanding what these funds actually do, how they differ from traditional active and passive funds, and what risks they carry is essential before adding one to your portfolio.

In the context of investing, momentum refers to the tendency of assets that have performed well over a recent historical period to continue performing well over the near future, and assets that have performed poorly to continue underperforming. It is a relative concept: a momentum stock is one that has outperformed its peers over the measurement window, not simply one that has risen in absolute terms.

The momentum effect was formally documented in academic research in the early 1990s, most prominently by Narasimhan Jegadeesh and Sheridan Titman in a 1993 paper that showed US stocks with strong prior 12-month returns significantly outperformed stocks with weak prior returns over the subsequent 3 to 12 months.

Since then, the finding has been replicated across dozens of countries, across asset classes including commodities and currencies, and across different time periods. It is now considered one of the most durable anomalies in financial markets.

Why does momentum exist? Several explanations have been offered. Behavioural finance researchers point to underreaction: investors are slow to incorporate new information fully into prices, causing a gradual drift upward in stocks where the news is good and a gradual drift downward where it is bad.

Others point to herding behaviour, where institutional investors gradually pile into recent winners. Still others point to delayed capital flows from passive index funds as a structural contributor. No single explanation has emerged as definitive, which is one reason researchers believe the effect is likely to persist.

Momentum is not a prediction that winners will keep winning forever. It is a statistical observation that, on average, recent outperformers tend to continue outperforming over the next several months before mean-reverting.

A momentum fund is a rules-based fund that systematically selects and holds stocks that have demonstrated strong recent price performance relative to their peers. The fund does not make qualitative judgements about management quality, competitive positioning, or earnings growth. It simply identifies stocks that have been rising faster than others and holds them, replacing them with new winners when the relative performance rankings shift.

Most momentum funds in India are structured as index funds or ETFs tracking a momentum index. The Nifty 200 Momentum 30 index and the Nifty 500 Momentum 50 index are two of the most commonly used underlying benchmarks. The methodology follows a defined process: calculate a momentum score for each eligible stock, rank the stocks by that score, and select the top performers into the portfolio.

The momentum score itself is typically calculated using past price returns over a defined lookback window, most commonly the last 12 months excluding the most recent month. The reason for excluding the most recent month is to avoid the short-term reversal effect, a separate phenomenon where very recent sharp moves tend to partially reverse in the immediate following weeks. By measuring 12-month returns and skipping the last month, the momentum score captures the medium-term trend while sidestepping the very short-term noise.

Step	What Happens	Purpose
Define the universe	Eligible stocks are drawn from a parent index such as Nifty 200 or Nifty 500	Sets the pool from which momentum stocks are selected
Calculate momentum score	Price return over 12 months excluding the most recent month, adjusted for volatility in some methodologies	Measures relative recent strength of each stock
Rank and select	Stocks ranked by momentum score; top 30 or 50 selected into the index	Concentrates exposure in the highest-momentum names
Weight the portfolio	Weights assigned based on momentum score, market cap, or a combination	Determines each stock's influence on fund returns
Rebalance	Index reconstituted semi-annually or quarterly; losers exit, new winners enter	Ensures the portfolio continuously reflects current momentum leaders

The rebalancing frequency matters considerably. Momentum is a medium-term phenomenon, and the portfolio needs to be refreshed regularly enough to stay current with shifting leadership, but not so frequently that transaction costs erode the advantage. Most Indian momentum indices rebalance every six months, with some doing so quarterly.

Indian investors have access to momentum strategies through several vehicle types, each with different structures, costs, and practical considerations.

Vehicle Type	How It Works	Key Feature
Momentum index fund	Passively tracks a momentum index such as Nifty 200 Momentum 30; priced at end-of-day NAV	Very low expense ratio; SIP-friendly; no active management decisions
Momentum ETF	Tracks the same indices but units trade on NSE or BSE like shares; real-time pricing	Intraday trading possible; requires demat account; tracking error a consideration
Actively managed momentum fund	Fund manager uses momentum signals alongside other criteria; more discretion than pure index	Can deviate from pure momentum screen; manager skill and consistency add another variable
Quant funds with momentum tilt	Rule-based multifactor funds that include momentum as one of several factors alongside quality, value, or low volatility	Blended exposure; may smooth extreme momentum drawdowns; harder to attribute performance to any single factor

Pure momentum index funds and ETFs are the most transparent option because the methodology is publicly disclosed and consistently applied. Actively managed funds that claim a momentum approach can vary significantly in how purely they implement the strategy, making performance attribution more difficult. For investors who want genuine momentum exposure, a fund that tracks a defined momentum index is the cleaner choice.

NSE Indices has developed several momentum indices that serve as benchmarks for funds in this category. The most widely used are the Nifty 200 Momentum 30 and the Nifty 500 Momentum 50.

The Nifty 200 Momentum 30 selects 30 stocks from the Nifty 200 universe. The momentum score is calculated using the normalised 6-month and 12-month price returns, and adjusted by the stock's volatility. Stocks with high returns relative to their volatility score more highly, which means the index does not simply chase the highest-return stocks regardless of how volatile they are. Weights are assigned based on a combination of momentum score and float-adjusted market capitalisation, and the index is rebalanced semi-annually.

The Nifty 500 Momentum 50 draws from the broader Nifty 500 universe and selects 50 stocks using a similar methodology. Because it draws from a larger and more diverse universe, it tends to have different sectoral tilts than the Nifty 200 Momentum 30 in any given period.

Index	Parent Universe	Number of Stocks	Rebalance Frequency
Nifty 200 Momentum 30	Nifty 200	30	Semi-annual (June and December)
Nifty 500 Momentum 50	Nifty 500	50	Semi-annual (June and December)
BSE Momentum Index	BSE 500	30	Semi-annual

At any rebalancing date, the sectoral composition of a momentum index can look dramatically different from the Nifty 50 or Nifty 500 baseline. During a bull market driven by a particular sector, that sector's stocks will dominate the momentum rankings and the index will be heavily concentrated in it. This sector concentration is a feature of how momentum works, not a design flaw, but it is important to understand before investing.

The long-term evidence in favour of the momentum factor across global markets is substantial. In India specifically, backtests of momentum strategies over periods covering multiple market cycles have generally shown that momentum indices have delivered returns that exceeded the broader market over long horizons, though with meaningfully higher volatility and sharper drawdowns during periods when momentum reverses.

Several characteristics of the Indian market may make it particularly amenable to momentum strategies. Retail investor participation is large and growing, and retail investors as a group tend to underreact to information and chase recent winners, which sustains momentum trends. The Indian market also has a long tail of mid and small-cap stocks that receive less analyst coverage and where price discovery is slower, creating more room for information to be gradually priced in.

The theoretical case for why momentum should continue to work rests on the persistence of the behavioural biases that create it. Underreaction to good news and overreaction to bad news, anchoring to recent prices, and herding are deeply ingrained tendencies. As long as these biases persist, the conditions that sustain momentum are likely to persist as well.

Momentum has worked historically because markets are not perfectly efficient. Prices drift toward fair value gradually, not instantly, and that drift is what momentum strategies are designed to capture.

Momentum is among the riskier equity factors when measured by the severity of its drawdown events. Understanding these risks is essential, because investors who enter momentum funds during a period of strong performance and exit during a drawdown will often have experienced the worst of both worlds.

The most characteristic risk is called a momentum crash. These are periods when recent winners suddenly become violent losers, and recent losers rebound sharply. Momentum crashes tend to happen at market inflection points: when a long bull market reverses, the stocks that had risen the most and therefore dominated momentum portfolios are precisely the ones that fall the hardest in the initial sell-off.

Simultaneously, beaten-down value stocks, which momentum portfolios would have been avoiding or underweight in, often rebound strongly from oversold levels. The momentum factor can experience very sharp, rapid losses during these reversals.

The Indian market provides an illustration of this pattern. During sharp market corrections, particularly those accompanied by sectoral rotation from recent high-flyers to previously unloved segments, momentum funds have at times suffered drawdowns that significantly exceeded the broader market. An investor who observes smooth performance in the preceding years may not be psychologically or financially prepared for the speed and severity of momentum-specific losses.

Risk Type	What It Means	How Severe Can It Be
Momentum crash	Sharp, rapid losses when market reverses and leadership rotates away from recent winners	Can be 30% to 50% drawdowns in severe cases; sharper than market-wide falls
Sector concentration	Portfolio heavily tilted to one or two sectors that led the recent rally	Amplifies losses when that sector corrects; little diversification benefit in that moment
High portfolio turnover	Semi-annual rebalancing replaces a significant portion of the portfolio each cycle	Generates realised capital gains; higher transaction costs embedded in index
Crowding	As momentum funds attract more assets, all funds buy the same stocks simultaneously at rebalancing	Entry costs rise; exit can become disorderly when many funds sell the same names at once
Tracking error in ETFs	ETF price and NAV can diverge from the index due to liquidity constraints in underlying stocks	Particularly relevant when momentum index holds less liquid mid and small-cap stocks
Recency bias in investors	Investors often buy momentum funds after strong recent performance, just before a reversal	Actual investor returns lag fund returns significantly when entry timing is poor

Momentum is one of several well-documented investment factors, alongside value, quality, low volatility, and size. Each factor has a different return profile, and they do not all perform well at the same time. Understanding how momentum compares helps investors decide whether it belongs in their portfolio and in what combination.

Factor	Core Idea	When It Tends to Outperform	How It Compares to Momentum
Momentum	Stocks with strong recent relative performance continue to outperform in the near term	Trending markets; sustained bull runs; periods of sector leadership	Highest volatility and sharpest drawdowns of any major factor; highest short-term return potential
Quality	Companies with high profitability, low leverage, and stable earnings outperform over time	Defensive periods; earnings uncertainty; economic slowdowns	More stable than momentum; lower drawdowns; complements momentum well in a portfolio
Value	Stocks trading at low prices relative to fundamentals outperform over the long run	Market recoveries; post-crash periods; late cycle	Often inversely correlated with momentum; what momentum sells, value tends to buy
Low Volatility	Less volatile stocks deliver better risk-adjusted returns over time	Bear markets; high uncertainty; defensive investor preference	Opposite temperament to momentum; low volatility tends to be underweight in momentum portfolios
Size (Small Cap)	Smaller companies outperform larger ones over long periods	Bull markets with broad participation; domestic consumption growth	Often complementary; many small and mid-cap stocks appear in momentum portfolios during bull runs

The inverse correlation between momentum and value is particularly important. Value investors buy stocks that have fallen or are unloved; momentum investors hold stocks that have risen and are popular. The two approaches are almost structurally opposed in their stock selection. This means a portfolio that combines momentum and value exposure can benefit from diversification across market regimes, with one factor compensating when the other is suffering.

Momentum index funds and ETFs investing primarily in equity are taxed as equity mutual funds, since they maintain at least 65 percent of their portfolio in equity at all times.

Momentum funds are not suitable for every investor, and the characteristics of the strategy make the fit very specific.

• Investors with long time horizons of seven years or more. Momentum funds can underperform significantly for extended periods, and investors need the runway to hold through those phases without losing conviction or capital they cannot afford to have temporarily reduced.

• Investors who can tolerate sharp, concentrated drawdowns. The combination of sector concentration and momentum crash risk means that a momentum fund can fall harder and faster than the broader market in adverse conditions. Investors who checked their portfolio in March 2020 or in other sharp corrections need to be honest about whether they could hold a fund that might be down 40 or 50 percent at such moments.

• Investors who understand what the fund is and why it is in their portfolio. Momentum funds are often bought after a run of strong performance. Investors who buy them without understanding the strategy will typically exit during the inevitable underperformance phase, realising losses and missing the subsequent recovery.

• Investors using it as a satellite, not a core, allocation. Most financial practitioners who recommend momentum funds suggest keeping exposure at 10 to 20 percent of the equity portfolio, complementing a core of broad market or quality-oriented funds. A portfolio entirely in momentum is taking on significant factor concentration risk.

• Investors who are comfortable with rules-based investing and do not need to understand every stock in the portfolio. Momentum portfolios at any given time may contain stocks that appear expensive, cyclical, or otherwise counterintuitive to a fundamentals-oriented investor. The strategy requires trusting the process even when individual holdings look uncomfortable.

Several practical factors are worth examining before committing to a momentum fund.

Expense ratio: Momentum index funds in India have expense ratios in the range of 0.20 to 0.50 percent, higher than plain Nifty 50 index funds but lower than most actively managed equity funds. The slightly higher cost reflects the more frequent rebalancing and the narrower, less liquid universe of some momentum indices.

Fund size and liquidity: A very small momentum fund AUM creates practical problems when the fund needs to rebalance, particularly if the momentum index shifts toward mid and small-cap stocks with limited daily trading volume. A fund with very small assets under management may face higher market impact costs at rebalancing, which can drag on returns relative to the index. Checking the fund's AUM and comparing it against the liquidity of its current holdings is a useful discipline.

Tracking error: For momentum ETFs, comparing the ETF's historical returns to the underlying index returns reveals how well the fund has been able to replicate the index. A high tracking error indicates that the fund is struggling to match the index, often due to liquidity constraints or cash management inefficiencies.

The rebalancing calendar: Being aware of when the underlying momentum index rebalances, typically June and December for major NSE Indices products, is useful for investors who are sensitive to short-term price movements. In the weeks before a scheduled rebalancing, stocks that are expected to enter the index often see buying pressure from funds that pre-position, and stocks expected to exit can see selling pressure.

Momentum funds systematically invest in stocks that have outperformed their peers recently, based on one of the most extensively documented patterns in financial research. In India, these funds primarily track momentum indices like the Nifty 200 Momentum 30 or Nifty 500 Momentum 50, rebalancing every six months to continuously hold the market's recent winners.

The historical case for the momentum factor is strong, and the tax treatment through index funds is efficient because rebalancing gains are not taxed directly in the investor's hands.

The risks are equally real. Momentum crashes, sector concentration, and the tendency of investors to buy after strong runs and exit during corrections are all well-documented hazards of this strategy. Momentum funds are best held as part of a diversified equity portfolio alongside other strategies, by investors who understand what they own, have long time horizons, and are mentally prepared for the strategy's characteristic volatility pattern.

Disclaimer: This article is for educational purposes only and does not constitute financial or investment advice. Momentum funds carry significant market risk including the risk of sharp drawdowns that may exceed broader market losses. Past performance of the momentum factor or any specific fund is not a guarantee of future results. Tax provisions cited are for FY2025-26 and subject to change. Please consult a SEBI-registered financial adviser before making investment decisions.