What an ETF fund is

An ETF (exchange-traded fund) is a collection of investments bundled together and sold as a single package. When you buy one share of an ETF, you own a small piece of many different stocks, bonds, or other assets inside it. The fund manager decides what goes in the bundle, and the price of that one share moves up and down based on what those underlying investments are worth.

The key difference from a mutual fund is how you buy and sell it. You trade an ETF on a stock exchange during market hours, the same way you would trade a single company's stock. A mutual fund, by contrast, you buy directly from the fund company, and the price is set once per day after the market closes. ETFs typically have lower fees than mutual funds, and you can see exactly what you own inside them.

Key Takeaways

  • An ETF holds many investments in one package, so buying one ETF share gives you exposure to dozens or hundreds of stocks or bonds at once.
  • You buy and sell ETF shares on a stock exchange during trading hours, and the price changes throughout the day like a stock price does.
  • ETFs usually charge lower annual fees than mutual funds because they are passively managed — they simply track an index rather than having a manager pick individual investments.
  • Common ETF types track stock indexes (like the S&P 500), bond markets, specific industries, or international markets.
  • You can hold an ETF in a regular brokerage account or inside a retirement account like an IRA or 401(k).

How ETF shares are priced and traded

An ETF's share price is determined by supply and demand on the exchange, just like a stock. If many people want to buy a particular ETF, its price goes up. If many people want to sell, the price goes down. This happens in real time during market hours — typically 9:30 a.m. to 4 p.m. Eastern time on weekdays when the U.S. stock market is open.

The underlying assets inside the ETF — the stocks or bonds it holds — also change in value. So an ETF's price reflects both what those assets are worth and how many people are buying or selling the fund itself. Most of the time, the ETF's price stays very close to the total value of everything inside it, divided by the number of shares outstanding. This is called the net asset value or NAV.

You can buy or sell an ETF through any brokerage account — online brokers, banks, or financial advisors. You place an order just as you would for a stock, and it executes during market hours. Some brokers charge a commission per trade; many now offer commission-free ETF trading.

Common types of ETFs and what they track

The most popular ETFs track broad stock market indexes. An index is a pre-set list of investments — for example, the S&P 500 index includes 500 large U.S. companies. An ETF that tracks the S&P 500 holds shares in all (or most) of those 500 companies, so when you buy one share of that ETF, you own a tiny piece of all 500. Other common index-tracking ETFs follow the Nasdaq-100, the Dow Jones Industrial Average, or the total U.S. stock market.

Beyond stock indexes, ETFs exist for nearly every investment category. Bond ETFs hold government or corporate debt. Sector ETFs focus on one industry — technology, healthcare, energy, or financials. International ETFs hold stocks from specific countries or regions. Commodity ETFs track the price of oil, gold, or agricultural products. Some ETFs use more complex strategies, like leveraged ETFs (which aim to amplify returns) or inverse ETFs (which aim to profit when markets fall).

Most ETFs are passively managed, meaning they simply hold whatever is in their target index and rebalance periodically. A smaller number are actively managed, meaning a fund manager picks and changes the holdings to try to beat the market. Actively managed ETFs typically charge higher fees.

Fees and expenses you pay

Every ETF charges an annual fee called an expense ratio. This is a percentage of your investment that the fund company takes each year to cover management, administration, and other costs. For a passively managed index ETF, this is often very low — sometimes 0.03% to 0.20% per year. For an actively managed ETF, it might be 0.50% to 1.50% or higher.

Beyond the expense ratio, you may pay a trading commission when you buy or sell, depending on your broker. Many brokers now offer commission-free trading on ETFs. You may also pay a bid-ask spread — the difference between what buyers are willing to pay and what sellers are asking. This spread is usually small for popular ETFs but can be wider for less-traded ones.

If you hold an ETF in a taxable account and it pays dividends or makes capital gains distributions, you may owe taxes on those. ETFs are generally more tax-efficient than mutual funds because of how they are structured, but this varies by the specific fund and your situation.

How ETFs fit into a portfolio

Many people use ETFs as the core of their investment portfolio because they offer broad diversification at low cost. Instead of buying 50 individual stocks, you can buy one broad market ETF and own pieces of hundreds of companies. This reduces the risk that any single company's poor performance will hurt your overall returns.

ETFs work in regular brokerage accounts, IRAs, 401(k)s, and other retirement accounts. Some employers offer ETFs as investment choices within their 401(k) plans. You can also use ETFs to build a specific strategy — for example, holding a mix of U.S. stock ETFs, international stock ETFs, and bond ETFs to match your risk tolerance and time horizon.

Because ETF prices move throughout the day, some investors use them for short-term trading, buying and selling frequently to try to profit from price swings. Others buy ETFs and hold them for decades as part of a long-term retirement strategy. Both approaches are common, though research suggests that frequent trading typically underperforms a buy-and-hold approach after accounting for costs and taxes.

ETFs versus mutual funds and individual stocks

An ETF sits between a mutual fund and individual stocks in terms of how it works. Like a mutual fund, an ETF gives you instant diversification — one purchase gets you many holdings. Like a stock, an ETF trades on an exchange with a price that changes throughout the day, and you can buy or sell it whenever the market is open.

Mutual funds are priced once per day after the market closes, so you do not know the exact price when you place your order. ETFs are priced continuously, so you see the price before you buy. Mutual funds often have higher expense ratios and may charge sales loads (upfront fees). Most ETFs have lower fees and no sales loads.

If you buy individual stocks, you own one company and bear the full risk if that company struggles. With an ETF, your risk is spread across many holdings. However, individual stocks can outperform an index if you pick well, whereas an index-tracking ETF will match the index's performance (minus fees). Most individual investors do not consistently beat the market, which is why many financial advisors recommend index ETFs as a core holding.

Frequently Asked Questions

Can I lose money in an ETF?

Yes. If the stocks or bonds inside the ETF fall in value, your ETF share price falls too. You can lose some or all of your investment. However, because an ETF typically holds many different investments, the risk is usually lower than owning a single stock. Diversification does not prevent losses, but it can reduce them.

Do I need a lot of money to start buying ETFs?

No. You can buy one share of an ETF for whatever that share costs — often between $20 and $150, depending on the fund. Some brokers allow fractional share purchases, so you can invest even smaller amounts. There is no minimum account balance at most brokers.

What is the difference between an ETF and an index fund?

An index fund is a mutual fund or ETF that tracks a specific index. So all index funds are either mutual funds or ETFs, but not all ETFs are index funds — some are actively managed and do not track an index. Index ETFs trade on an exchange like stocks; index mutual funds trade through the fund company once per day.

Can I hold an ETF in a retirement account?

Yes. You can hold ETFs in an IRA, 401(k), or other retirement account. Many 401(k) plans offer ETFs as investment choices. Holding ETFs in a retirement account can be tax-efficient because you do not pay taxes on gains or dividends until you withdraw the money (or in a Roth account, potentially never).

How do I know which ETF to buy?

Consider your investment goals, time horizon, and risk tolerance. If you want broad market exposure, a low-cost index ETF tracking the S&P 500 or total market is a common starting point. Compare expense ratios across similar funds — lower is usually better. Look at trading volume to ensure the ETF is liquid enough to buy and sell easily. Many brokers and financial websites provide ETF comparison tools and research.