Both track an index. Both charge very little. The difference is entirely mechanical — how you buy them, what you actually pay, and what can go wrong.
Those mechanics matter more in India than the usual comparison suggests, because liquidity on several Indian ETFs is thinner than people assume.
How each one actually works
An index fund is a mutual fund scheme. You place an order with the fund house, and units are created or redeemed at the day's NAV, calculated after the market closes. Everyone transacting that day gets the same price. No demat account is needed and no counterparty is involved.
An ETF is listed on the exchange and traded like a share. You need a demat account, you buy from another participant at whatever price is quoted, and the price you get depends on who is selling at that moment. Its value tracks the index, but what you pay is set by supply and demand in the order book.
That is the whole distinction, and every practical difference below follows from it.
Impact cost, which is the real Indian issue
The one that decides this for most retail investors here.
An index fund has no spread. You get the NAV, whatever the size of your order.
An ETF has a bid and an ask, and on a thinly traded one that gap can be wide. On the largest and most liquid Indian ETFs it is negligible. On smaller or more specialised ones it can exceed a year of the fund's expense ratio in a single transaction — which turns the ETF's headline cost advantage into a loss on entry.
Worse, an ETF can trade away from the value of what it holds. If few people are trading it, the quoted price can sit at a premium or a discount to the underlying basket. Buying at a premium means paying more than the holdings are worth, and it is invisible unless you check.
What to do about it. Compare the quoted price against the iNAV, the indicative value published through the session, before placing an order. Use limit orders rather than market orders. And avoid the opening and closing minutes, when spreads are widest.
If those three steps sound like more attention than you want to give, that is itself the answer — an index fund removes all of them.
Tracking error and cost, honestly compared
Expense ratio. ETFs are usually cheaper, sometimes meaningfully. That is the headline case for them and it is real for a long holding.
Tracking error. How closely the product follows its index over time. Both have it, and it is not always lower for the cheaper product — a fund's cash holdings, its rebalancing and the timing of dividend reinvestment all contribute. Compare tracking error alongside expense ratio rather than assuming the lower fee wins.
Transaction costs. This is where the comparison usually turns. An ETF adds brokerage, STT, exchange charges, GST, stamp duty and the spread on every purchase and sale. An index fund purchase has none of those.
The arithmetic that matters: a small annual saving on expense ratio takes years to repay a wide spread paid on entry. For a lump sum held for a decade in a liquid ETF, the ETF likely wins. For monthly investments of modest size, the transaction costs recur every month and the index fund usually wins.
The practical differences that decide it
Recurring investment. Index funds support a straightforward recurring instruction that buys a rupee amount, fractional units included. Buying an ETF monthly means placing an order each time, in whole units, at whatever price the market offers. Some platforms automate it; it remains a market transaction rather than a subscription.
Demat account. ETFs require one. Index funds do not, which matters for somebody who wants nothing to do with a trading account.
Intraday pricing. An ETF can be bought and sold during the session. That is presented as an advantage and, for a long-term investor, is closer to a temptation.
Dividends. Handling differs between products, and reinvestment is not automatic in every case. Check what the specific product does.
Minimum size. An index fund accepts small recurring amounts. An ETF's minimum is the price of one unit.
Which one suits you
Index fund, if you invest monthly, want a recurring instruction you can forget about, prefer not to hold a demat account, or would rather not think about spreads and order types at all. This covers most people building wealth from a salary, and it is the default recommendation for that reason.
ETF, if you are deploying a lump sum, the specific ETF is genuinely liquid, you are comfortable checking iNAV and using limit orders, and you intend to hold for years so the lower expense ratio has time to compound in your favour.
Either, if you already hold a demat account and the ETF you want is one of the large liquid ones. At that point the difference is small enough that the more important decision is which index, not which wrapper.
That last point is worth ending on. Arguing between an ETF and an index fund tracking the same index is a smaller decision than which index you track and how consistently you keep buying it. Both of those matter more over a decade than the wrapper does.
An ETF needs a demat account; an index fund does not, though most platforms offer both from the same login.
One account usually covers both
Check iNAV and use limit orders if you go the ETF route. Free to open
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Frequently Asked Questions
What is the difference between an ETF and an index fund?
An index fund transacts with the fund house at the day's NAV and needs no demat account. An ETF is listed and bought from another participant at whatever the order book offers, so the price depends on liquidity at that moment.
Are ETFs cheaper than index funds in India?
On expense ratio, usually. In total cost, not always - an ETF adds brokerage, STT, exchange charges, GST, stamp duty and the spread on every transaction. A wide spread on entry can exceed a year of the expense ratio saving.
What is iNAV and why should I check it?
The indicative value of the ETF's underlying holdings, published through the session. A thinly traded ETF can quote at a premium or discount to it, so checking before you order tells you whether you are paying more than the holdings are worth.
Can I do a monthly SIP into an ETF?
Some platforms automate it, but it remains a market transaction in whole units at whatever price is quoted, with costs each time. Index funds handle recurring investment more cleanly, including fractional units, which is why they suit monthly investing better.
Which should I choose?
Index fund for monthly investing from a salary, no demat account and no thinking about spreads. ETF for a lump sum into a genuinely liquid product held for years. And either way, which index you track matters more over a decade than which wrapper you use.
Related Reading
- Index funds vs stocks
- SIP or lumpsum?
- Order types: market, limit, SL and SL-M
- Dividend investing in India
- Stock Market for Beginners - full syllabus
Disclaimer: TheFinBaba provides educational content only - this is not investment advice. Trading involves risk of loss.
