Index Funds in India: Why They Beat Most Active Funds Over Time

What is an index fund?

An index fund is a type of mutual fund that aims to replicate the performance of a specific market index — such as the Nifty 50, the Sensex, the Nifty Next 50, or the Nifty Midcap 150 — by holding the same stocks in the same proportions as the index. The fund does not attempt to outperform the index; its sole objective is to match it as closely as possible.

This approach is called passive investing. The fund manager's role is mechanical: when the index composition changes (for example, when a stock is added to or removed from the Nifty 50 during the semi-annual rebalancing), the fund adjusts its portfolio accordingly. There is no discretionary stock selection, no sector bets, no market-timing calls. The fund simply mirrors the index.

The concept was pioneered by John Bogle, who launched the first index fund for retail investors in the United States in 1976. In India, index funds gained meaningful traction only from 2018 onwards, driven by two factors: SEBI's mutual fund categorisation circular (which restricted large-cap funds to the top 100 stocks, limiting their ability to generate alpha through mid-cap holdings) and the growing body of evidence from SPIVA reports showing widespread active fund underperformance.

How passive investing works in practice

When an investor puts Rs 10,000 into a Nifty 50 index fund, the fund allocates that capital across all 50 stocks in the Nifty 50 in proportion to their index weight. As of January 2025, the three largest weights in the Nifty 50 were Reliance Industries, HDFC Bank, and ICICI Bank — together accounting for approximately 25-30% of the index. A Nifty 50 index fund would hold these three stocks at approximately the same percentage of its portfolio.

The fund rebalances its portfolio whenever the index changes:

• Semi-annual reconstitution: NSE reviews the Nifty 50 composition in March and September each year. Stocks that no longer meet the eligibility criteria are replaced by stocks that do. The index fund must sell the exiting stock and purchase the entering stock to maintain alignment.
• Weight adjustments: as stock prices move, index weights change. The fund periodically rebalances to ensure its holdings match the updated weights. Free-float adjustments by the index provider also trigger portfolio changes.
• Corporate actions: stock splits, bonus issues, and mergers within index constituents require the fund to adjust holdings.

The entire process is rule-based. The fund manager follows the index methodology document published by NSE Indices (for Nifty indices) or Asia Index Private Limited (for Sensex indices). There is no room for personal judgment — which is precisely the point.

Tracking error: the quality metric for index funds

Since an index fund aims to replicate its benchmark, the key quality metric is not absolute return but tracking error— the degree to which the fund's return deviates from the index's return.

Tracking error arises from several sources:

• Expense ratio:the TER is deducted from the fund's assets daily, creating a systematic drag versus the index (which has no costs). A fund with a 0.10% TER will underperform the index by approximately 0.10% per annum, all else being equal.
• Cash drag: index funds hold a small cash balance to handle redemptions and incoming SIP flows. This cash earns less than the equity portfolio, creating a minor performance drag.
• Rebalancing timing: when the index reconstitutes, the fund cannot instantaneously buy and sell all affected stocks. The brief delay and market impact of large trades create small deviations.
• Dividend reinvestment timing: when a constituent stock pays a dividend, there is a brief lag before the fund reinvests the dividend proceeds, during which the cash sits idle.

A well-managed Nifty 50 index fund in India typically exhibited an annualised tracking error of 0.02-0.10% as of early 2025. When comparing two index funds tracking the same benchmark, the one with the lower tracking error (and lower expense ratio) is objectively superior — there is no subjective judgment involved.

Major Indian indices for index fund investing

The Indian market offered index funds tracking several major benchmarks, each representing a different slice of the market:

• Nifty 50: the 50 largest companies by free-float market capitalisation on the NSE. Represented approximately 58-62% of total NSE market capitalisation. The most widely tracked index and the benchmark for most large-cap funds.
• Sensex (S&P BSE Sensex): the 30 largest companies on the BSE. Historically the most recognised Indian market index, though the Nifty 50 surpassed it in terms of fund tracking and institutional use.
• Nifty Next 50:companies ranked 51-100 by market capitalisation — the "waiting room" for the Nifty 50. Offered higher growth potential with higher volatility than the Nifty 50. Several AMCs launched index funds tracking this index.
• Nifty Midcap 150: companies ranked 101-250 by market capitalisation. Represented the mid-cap segment and offered index fund exposure to a space traditionally dominated by active funds.
• Nifty Smallcap 250: companies ranked 251-500 by market capitalisation. Index funds tracking this index provided broad small-cap exposure, though liquidity and tracking error challenges were more pronounced.
• Nifty 500: the broadest NSE equity index, covering the top 500 companies. A Nifty 500 index fund offered market-wide diversification across large, mid, and small-cap segments in a single fund.

Historical returns of the Nifty 50

The Nifty 50 Total Return Index (TRI) — which includes dividend reinvestment — delivered the following annualised returns over various periods ending December 2024 (all figures are historical and do not indicate future performance):

• 5-year annualised return (Dec 2019 - Dec 2024): approximately 14-15% per annum. This period included the March 2020 crash and the subsequent recovery rally.
• 10-year annualised return (Dec 2014 - Dec 2024): approximately 12-13% per annum. This period spanned demonetisation, GST implementation, the IL&FS crisis, Covid-19, and the post-pandemic bull run.
• 15-year annualised return (Dec 2009 - Dec 2024): approximately 12-14% per annum. Starting from the recovery phase after the 2008 global financial crisis.
• 20-year annualised return (Dec 2004 - Dec 2024): approximately 13-15% per annum. This encompassed two complete bull and bear cycles.

These returns — in the range of 12-15% annualised over long periods — represented the "market return" that any investor could have captured simply by holding a Nifty 50 index fund. The critical question for active fund selection was whether paying 1-1.5% higher in expense ratios for an active fund consistently added value above this baseline.

Why most active large-cap funds underperformed the Nifty 50

The SPIVA (S&P Indices Versus Active) India Scorecard, published semi-annually by S&P Dow Jones Indices, tracked the performance of actively managed Indian mutual funds against their benchmarks over various periods. The findings were consistent and striking:

• Over the 5-year period ending June 2024, the SPIVA India report found that approximately 73-85% of actively managed Indian large-cap equity funds underperformed the S&P BSE 100 (the large-cap benchmark used in the SPIVA methodology). The exact percentage varied by reporting period, but the direction was consistently the same: a clear majority of active large-cap funds failed to beat their benchmark.
• Over 10-year periods, the underperformance rate was typically even higher — often exceeding 80-90% of active large-cap funds.
• The underperformance was particularly pronounced after SEBI's 2017 categorisation circular, which required large-cap funds to invest at least 80% of assets in the top 100 stocks by market capitalisation. Before this circular, many large-cap funds enhanced returns by holding 20-30% in mid-cap stocks — a strategy that inflated their apparent alpha but carried higher risk than a true large-cap mandate.

The implication was clear: for large-cap equity exposure in India, a low-cost index fund was the more rational default choice for the majority of investors. The active fund that genuinely and consistently outperformed its benchmark after costs was the exception, not the rule.

The expense ratio advantage

The cost advantage of index funds over active funds was the most tangible and predictable edge:

• Nifty 50 index funds (direct plan): TER of 0.10- 0.20% per annum as of early 2025. The most competitively priced schemes charged as low as 0.10%.
• Actively managed large-cap funds (direct plan): TER of 1.0-1.5% per annum — approximately 5-15x higher than a comparable index fund.
• Actively managed large-cap funds (regular plan): TER of 1.5-2.1% per annum — approximately 10-20x higher than a direct index fund.

Over 20 years, a 1% annual expense ratio difference on a Rs 10,000 monthly SIP can compound into a difference of Rs 15-20 lakh in the final corpus, even if both funds generated identical gross returns. For a detailed breakdown of how expense ratios compound, see our guide on mutual fund expense ratios. You can model the impact on your own SIP using our SIP calculator.

When active funds still made sense

The case for passive investing was strongest in the large-cap segment. In mid-cap and small-cap segments, the evidence was more nuanced:

• Mid-cap active funds: SPIVA India reports showed that the underperformance rate for mid-cap active funds was lower than for large-cap funds — roughly 50-65% of mid-cap active funds underperformed over 5-year periods, compared to 75-85% of large-cap funds. The mid-cap universe (ranks 101-250 by market capitalisation) was less efficiently researched and priced, providing more opportunities for skilled stock-pickers.
• Small-cap active funds: the small-cap segment (ranks 251-500+) was the least efficient, with wider bid-ask spreads, lower institutional coverage, and more pricing inefficiencies. Skilled active managers had historically generated meaningful alpha in this segment, though with significantly higher volatility.
• Tactical allocation: balanced advantage funds and dynamic asset allocation funds — which actively shifted between equity and debt based on valuation metrics — provided a form of active management that index funds could not replicate, as they combined asset allocation decisions with equity exposure.

A reasonable approach for many investors was to combine passive index fund exposure for large-cap allocation with selective active fund exposure for mid-cap and small-cap allocation — capturing the cost advantage of indexing where it mattered most while retaining the potential alpha from active management where the evidence supported it.

Index fund vs ETF: key differences

Both index mutual funds and ETFs (Exchange-Traded Funds) are passively managed and track a benchmark index. However, they differ in several practical aspects:

• Trading mechanism: an index mutual fund is purchased and redeemed at the end-of-day NAV, like any other mutual fund. An ETF is traded on the stock exchange during market hours, with prices fluctuating throughout the day.
• Demat requirement: ETFs require a demat account and a trading (brokerage) account. Index mutual funds do not — they can be purchased directly from the AMC or through platforms like MF Central, Kuvera, or INDmoney without any demat account.
• SIP convenience: SIPs in index mutual funds are straightforward — the AMC handles the automatic NAV-based unit allotment. ETF SIPs are available through some brokers but are less seamless, as the purchase happens at market price (not NAV) and involves brokerage charges on each transaction.
• Liquidity and pricing: ETFs can trade at a premium or discount to NAV, depending on market demand and market-maker activity. Low-liquidity ETFs (with wide bid-ask spreads) may result in the investor paying meaningfully more than NAV when purchasing or receiving less than NAV when selling. Index mutual funds always transact at NAV, eliminating this concern.
• Expense ratio: ETFs generally had slightly lower expense ratios than the corresponding index mutual fund from the same AMC, as the ETF does not bear SIP processing and RTA costs for individual folios. The difference was typically 0.01-0.05%.

For most retail investors, particularly those investing via SIP without a demat account, index mutual funds offered greater convenience. ETFs were more suitable for large lumpsum investments where intraday pricing flexibility and marginally lower TER were advantageous.

How to invest in an index fund

The process of investing in an index fund is identical to investing in any other mutual fund in India:

1. Complete KYC: one-time eKYC through any mutual fund platform or AMC website. Aadhaar-based eKYC takes minutes.
2. Select the index and scheme: decide which index you want to track (Nifty 50, Nifty Next 50, etc.) and compare the available index funds on expense ratio and tracking error. Choose the direct plan — see direct vs regular plans to understand why.
3. Choose growth option: for long-term wealth creation, the growth option reinvests all returns within the fund, maximising compounding.
4. Set up SIP or invest lumpsum: register a SIP mandate via NACH or UPI autopay for regular investing. For a one-time investment, place a lumpsum purchase order through the platform. See our guide on what is SIP for the mechanics of systematic investing.
5. Monitor annually:check the fund's tracking error and expense ratio once a year. If a competitor index fund tracking the same benchmark has materially lower tracking error and TER, consider switching — but account for tax implications before doing so.

The bottom line

Index funds represent the most important shift in Indian mutual fund investing over the past decade. The evidence — from SPIVA reports, from rolling return comparisons, from the mathematics of compounding expense ratios — consistently pointed to the same conclusion: for large-cap equity exposure, a low-cost index fund was the most rational default choice for the majority of Indian retail investors.

This does not mean active funds have no role. In mid-cap and small-cap segments, where market efficiency is lower, skilled active management has historically added value in India. But for the core large-cap allocation — which forms the foundation of most long-term equity portfolios — an index fund with a 0.10-0.20% expense ratio delivered the market return at minimal cost, while the majority of active alternatives charged 10-15x more and failed to keep up.

Frequently asked questions

What is the minimum amount to invest in an index fund?

Most index funds in India accepted lumpsum investments starting from Rs 500-1,000 and SIP investments starting from Rs 100-500 per month as of early 2025. The exact minimum depends on the AMC and the specific scheme.

Is an index fund the same as an ETF?

No. Both are passively managed and track a benchmark index, but an index mutual fund is purchased at end-of-day NAV through the AMC or a platform, while an ETF is traded on the stock exchange with intraday price fluctuations. ETFs require a demat account; index mutual funds do not. For SIP investors, index mutual funds are typically more convenient.

Do index funds pay dividends?

Index funds offer both growth and IDCW options. In the growth option, dividends received from underlying stocks are reinvested in the fund. In the IDCW option, periodic distributions are made and taxed at the investor's slab rate. Most long-term investors chose the growth option for tax efficiency and uninterrupted compounding.

Can I lose money in an index fund?

Yes. An index fund's value tracks the underlying index. If the Nifty 50 declines by 30%, a Nifty 50 index fund would also decline by approximately 30%. Index funds eliminate stock-selection risk but do not protect against market risk. Over long holding periods (10+ years), major Indian equity indices have historically recovered from every major decline, but past patterns do not guarantee future outcomes.