If you are new to investing, the terms index fund, ETF and mutual fund can be confusing. They are related, and the differences matter for cost, convenience and taxes. This guide breaks them down in plain language.
What is a fund?
A fund pools money from many investors and uses it to buy a collection of investments, such as stocks or bonds. Instead of picking individual companies, you own a small slice of a large, diversified basket. Diversification spreads risk, so one company doing badly matters less.
What is an index fund?
An index fund aims to match the performance of a market index, such as the S&P 500 in the United States, rather than beat it. It simply holds the same companies as the index. Because there is little active decision-making, index funds usually have low fees. An index fund can be structured as either a mutual fund or an ETF.
What is a mutual fund?
A mutual fund is bought and sold directly through the fund company or a broker, and its price is set once per day after markets close, based on the value of its holdings (called net asset value). Some mutual funds are actively managed by professionals who try to beat the market; others are index funds. Some require a minimum initial investment.
What is an ETF?
An exchange-traded fund (ETF) trades on a stock exchange throughout the day, just like a share of stock. Most ETFs track an index, although some are actively managed. ETFs often have low costs and low or no minimums, and you can usually buy a single share or sometimes even a fraction of one.
| Feature | Index fund | ETF | Mutual fund |
|---|---|---|---|
| Goal | Match an index | Usually match an index | Match an index or try to beat it |
| How you trade | Depends on structure | Anytime the market is open | Once a day at closing price |
| Typical costs | Low | Low | Varies, can be higher if active |
| Minimum to start | Varies | Often one share or less | Sometimes a set minimum |
Fees to watch
The most important number is the expense ratio, the annual fee taken as a percentage of your investment. A fund charging 1% costs $100 a year on $10,000; one charging 0.05% costs $5. Over decades, the difference compounds into a large amount. Also watch for trading commissions, sales loads and account fees.
Active vs passive: does it matter?
Research, including regular reports by S&P Dow Jones Indices, has repeatedly found that most actively managed funds fail to beat their benchmark index over long periods, especially after fees. That is a major reason low-cost index investing is popular. It does not guarantee any fund will do well, and past performance never guarantees future results.
How to choose
- Look for broad diversification, such as a total market or world index.
- Compare expense ratios and choose low-cost options.
- Check whether your platform charges to trade or requires a minimum.
- Match the fund to your goal and how long you can leave the money invested.
- Read the fund's official documents before investing.
Frequently asked questions
Are ETFs safer than mutual funds?
Neither is automatically safer. Risk depends on what the fund holds, not its structure.
Can I lose money in an index fund?
Yes. If the market falls, the value of an index fund falls too.
Which is better for beginners?
Many beginners prefer low-cost, broadly diversified index funds, whether as ETFs or mutual funds. The best choice depends on your platform and goals.
This article is for general educational purposes only and is not financial, investment, tax or legal advice. Rules, rates and figures change and differ by country, so check current information and consider speaking with a licensed professional before making decisions.