Index Funds
Index funds are passive mutual funds that invest at least 95% of their assets in the securities of a chosen index, such as the Nifty 50 or Sensex, aiming to match the index's returns at low cost.
What Is an Index Fund?
An index fund is a mutual fund that copies a market index instead of trying to beat it. If the index is the Nifty 50, the fund buys the same 50 stocks in roughly the same proportions. Under SEBI's scheme categorisation rules, an index fund must invest at least 95% of its total assets in the securities of the index it replicates or tracks.
Because there is no stock picking, index funds are called passive funds. Their goal is simple: deliver the index's return, minus a small cost. They are bought and redeemed directly with the fund house at NAV, just like any other open-ended mutual fund, so you do not need a demat account.
How Does an Index Fund Work?
- Choose an index: The scheme names the index it tracks, for example a large-cap, mid-cap, sectoral, factor or bond index.
- Replicate the portfolio: The fund holds the index's constituents in their index weights.
- Rebalance with the index: When the index provider adds, removes or reweights stocks, the fund adjusts its holdings.
- Manage cash flows: New money is invested and redemptions are paid with minimal deviation from the index.
- Report tracking: The fund discloses how closely it has followed the index.
Tracking error and tracking difference
- Tracking error measures how much the fund's daily returns vary from the index's daily returns. SEBI's norms, as reflected in scheme documents, cap tracking error for equity index funds and ETFs at 2% (annualised, based on one-year rolling data), except in situations beyond the fund house's control. Funds disclose it daily on AMC and AMFI websites.
- Tracking difference is the simple gap between the fund's return and the index's return over a period, mainly due to expenses and cash holdings.
Practical Example
Illustrative: one-year comparison. You invest ₹1,00,000 in an index fund. The index returns 12% in a year.
- Index value of ₹1,00,000 = ₹1,12,000
- If the fund returns 11.75% (difference of 0.25 percentage points due to costs and cash), your investment = ₹1,11,750
- Tracking difference = ₹1,12,000 − ₹1,11,750 = ₹250
Illustrative: cost over time. Assume a gross market return of 12% a year for 10 years on ₹1,00,000.
- Fund with 0.2% annual cost → net 11.8% → ₹1,00,000 × 1.118^10 ≈ ₹3,05,083
- Fund with 1.2% annual cost → net 10.8% → ₹1,00,000 × 1.108^10 ≈ ₹2,78,867
- Difference ≈ ₹26,216
This simplification assumes both earn the same gross return. An active fund may earn more or less than the index; the point is that costs compound. All figures are hypothetical.
Why Is It Important?
- Low cost: Index funds usually have lower expense ratios than actively managed funds.
- No manager risk: Returns do not depend on one manager's stock picks.
- Transparency: You know the holdings because they mirror the index.
- Market returns, not more: You will never beat the index; you get its ups and downs, minus costs.
Key Features
| Feature | Index fund |
|---|---|
| SEBI minimum | 95% in securities of the tracked index |
| Management style | Passive |
| How to buy | Directly from AMC or via distributors and platforms, at NAV |
| Demat account | Not required |
| Key metrics | Expense ratio, tracking error, tracking difference |
| Typical uses | Core equity holding, low-cost SIPs |
Tax treatment
Taxation depends on what the fund tracks. Equity index funds and equity ETFs that keep at least 65% in domestic listed equity are taxed as equity-oriented funds: as per rules applicable from 23 July 2024, 20% on gains for units held up to 12 months, and 12.5% on gains above ₹1.25 lakh a year for units held longer, plus surcharge and cess. Debt index funds and debt ETFs investing more than 65% in debt and money market instruments are specified mutual funds from FY 2025-26, so gains on units bought from 1 April 2023 are taxed at slab rates. Gold, silver and international products follow other rules. Check the provisions in force for your year or consult a tax adviser.
Benefits and Limitations
| Benefits | Limitations |
|---|---|
| Low costs | Cannot outperform the index |
| Simple and transparent | Falls fully with the market; no defensive moves |
| Removes manager-selection risk | Index concentration (for example, heavy weight in a few sectors) passes to you |
| Easy SIP investing without demat | Tracking error and difference reduce returns slightly |
Comparison With Related Concepts
| Concept | Meaning | Key difference | Practical implication |
|---|---|---|---|
| Index fund | Mutual fund copying an index | Bought and sold with AMC at end-of-day NAV | No demat needed; SIP-friendly |
| ETF | Fund copying an index, listed on an exchange | Traded during market hours at market prices | Needs demat; brokerage and bid-ask spread apply |
| Active fund | Manager selects stocks | Aims to beat the benchmark | Higher cost; may outperform or underperform |
| Fund of Funds | Invests in other funds | Extra layer | Possible additional costs |
See also Index Funds vs ETFs and Active vs Passive Funds.
How Does It Apply to Mutual Fund Investors?
- Choosing between index funds on the same index: Compare expense ratio, tracking error, tracking difference and fund size.
- Choosing the index: A broad large-cap index is very different from a sectoral or small-cap index; the index decides the risk.
- SIPs: Index funds are well suited to automatic SIPs.
- Monitoring: Instead of checking whether the fund "beat the market", check whether it tracked the index closely.
Common Mistakes and Misconceptions
- "Index funds are risk-free because they are diversified." They carry full market risk; if the index falls 30%, so does the fund.
- "All index funds are the same." Funds tracking different indices behave very differently, and even funds on the same index differ in costs and tracking.
- "Low cost means guaranteed better returns than active funds." Costs are a known drag, but some active funds may outperform in some periods.
- "I need a demat account for index funds." You do not; that is required for ETFs.
Important Terms to Know
- Tracking Error: Variation of fund returns from index returns.
- Benchmark Index: The index a fund tracks or is measured against.
- Exchange-Traded Funds (ETFs): Index-tracking funds traded on exchanges.
- Active vs Passive Funds: Managed funds versus index-tracking funds.
- Expense Ratio: The annual cost of running a fund.
- Index Funds vs ETFs: A comparison of the two passive routes.
Key Takeaways
- Index funds copy a chosen index and must invest at least 95% in its securities.
- Their aim is to match the index, minus costs, not to beat it.
- Compare index funds by expense ratio, tracking error and tracking difference.
- The index you choose determines your risk.
- No demat account is needed, making them easy for SIPs.
Related Glossary Terms
- Exchange-Traded Funds (ETFs)
- Index Funds vs ETFs
- Active vs Passive Funds
- Tracking Error
- Benchmark Index
- Expense Ratio
References
- SEBI circular: Categorization and Rationalization of Mutual Fund Schemes (26 February 2026)
- AMFI Knowledge Centre: Categorization of Mutual Fund Schemes
- Income Tax Department: Tax on long-term capital gains
- Income Tax Department: Section 76, Income-tax Act, 2025 (specified mutual funds)
Educational Disclaimer
This content is for educational and informational purposes only. It is not personalised investment, tax or legal advice, and it does not recommend any specific scheme. Mutual fund investments are subject to market risks; read all scheme-related documents carefully. Rules and tax provisions mentioned here reflect our understanding at the time of writing and can change. Before investing, consider your financial goals, risk profile and investment horizon, and consult a qualified professional where needed.
Explore Index Funds vs ETFs and Tracking Error in the FynnChintan Financial Glossary to keep learning. Beyond Numbers. Into Opportunities.
Frequently Asked Questions
What is the difference between an index fund and an ETF?
Both track an index. An index fund is bought and redeemed with the fund house at the day's NAV and needs no demat account. An ETF is traded on the stock exchange at market prices during the day and requires a demat and trading account.
Are index funds good for beginners?
Index funds are often considered beginner-friendly because they are simple, low-cost and do not depend on a fund manager's skill. You still need to pick an index that suits your goals and accept that the fund will rise and fall with the market.
Are index funds taxed differently from active funds?
No. Taxation depends on the underlying assets, not on whether the fund is active or passive. An equity index fund is taxed like other equity-oriented funds; a debt index fund is taxed like other debt funds.
Can index funds give negative returns?
Yes. If the index falls, the fund falls too. Index funds aim to match the index, not protect against losses. Over longer periods, broad equity indices have historically risen, but past performance does not guarantee future results.
What is tracking error in an index fund?
Tracking error measures how much an index fund's daily returns deviate from its index. Lower tracking error means closer tracking. As reflected in scheme documents, SEBI's norms cap it at 2% for equity index funds and ETFs, except in force majeure situations.
How do I choose between two index funds on the same index?
Compare their expense ratios, tracking error, tracking difference over one to three years, and fund size. Since both hold the same stocks, lower costs and closer tracking usually matter most.
This explanation is for general education only and is not investment advice. Mutual fund investments are subject to market risks; read all scheme-related documents carefully.