Index Funds Explained

Most great investing ideas are simple. Index funds sit at the top of that list. They are a vehicle so straightforward that finance professionals spent decades dismissing them — until decades of data proved they beat almost everyone.

What is an index?

An index is just a list. The NIFTY 50, for example, is a list of the 50 largest publicly traded companies in India. The index exists solely to track how these companies perform as a group. When people say "the market went up 1.2% today," they usually mean an index went up.

What is an index fund?

An index fund is a mutual fund (or ETF) that simply buys every stock in that list, in proportion to its weight. If Reliance is 10% of the NIFTY 50, your index fund puts 10% of its money into Reliance.

That's it. There is no fund manager making calls. No research team. No stock picks. Just a mechanical mirror of the index.

Why do index funds outperform most active funds?

In any given year, roughly 80% of actively managed funds in India underperform their benchmark index. Over a 10-year period, that number rises above 90%. There are three structural reasons:

• Costs compound against you. An actively managed fund charging 1.5% per year needs to outperform the index by 1.5% just to break even — before taxes.

• Markets are efficient. By the time you hear about a stock opportunity, it's already priced in. Fund managers fight the same battle with less edge than assumed.

• Manager luck vs. skill. Sustained outperformance is vanishingly rare. Most "star" managers revert to the mean within five years.

“Don't look for the needle in the haystack. Just buy the haystack.”

— Jack Bogle, founder of Vanguard

How to invest in an index fund in India

The simplest approach: open a Zerodha, Groww, or Coin account. Search for a NIFTY 50 or NIFTY 500 index fund from a low-cost AMC like UTI, Mirae, or HDFC. Start a SIP of whatever amount you can consistently afford.

• Look for an expense ratio below 0.2% for index funds (not 1.5% like active funds).

• Prefer funds from large AMCs with low tracking error.

• NIFTY 50 for large-cap exposure, NIFTY 500 for broader market exposure.

The one downside

Index funds guarantee you will never beat the market. You will also never significantly underperform it. For most people accumulating wealth over decades, that trade is excellent. You give up the lottery ticket in exchange for the guaranteed payout.