ETFs are funds that hold many stocks or bonds, trade like individual stocks, and usually cost less than actively managed funds

An exchange-traded fund (ETF) is a basket of investments — stocks, bonds, or a mix — that you buy and sell through a brokerage account the same way you would buy a single company's stock. The fund itself holds dozens, hundreds, or sometimes thousands of individual securities. When you own one share of an ETF, you own a tiny piece of everything inside it.

The main reason people choose ETFs over buying individual stocks is cost and simplicity. A single ETF might give you exposure to 500 companies at once. You pay one fee per year (called an expense ratio), which is usually between 0.03% and 0.50% of what you invest. That means on a $10,000 investment in a low-cost ETF, you might pay $3 to $50 per year. An actively managed mutual fund doing similar work often costs two to three times as much.

ETFs also trade during market hours, so you can buy or sell whenever the stock market is open. Mutual funds only trade once per day after the market closes. For most long-term investors, this does not matter much, but it matters if you need to move money quickly.

Key Takeaways

  • Index ETFs track a specific group of stocks or bonds (like the S&P 500) and have lower fees than funds that try to beat the market.
  • Your choice depends on your time horizon, how much risk you can handle, and whether you want broad market exposure or focus on specific sectors or themes.
  • A simple starting approach for long-term investors is one or two broad index ETFs covering U.S. stocks and international stocks, plus one bond ETF.
  • Expense ratio matters: a difference of 0.10% per year compounds over decades, so compare fees before you decide.
  • You buy and sell ETFs through a brokerage account (not directly from the fund company), and most brokerages now charge zero commission per trade.

Index ETFs versus actively managed ETFs

Most ETFs are index ETFs, meaning they track a published list of securities — the S&P 500, the Nasdaq-100, the total U.S. bond market, or others. The fund manager's job is simply to hold the same securities in the same proportions as the index, so the fund's performance matches the index's performance (minus the small expense ratio). Because this requires little active decision-making, index ETFs charge very low fees.

Some ETFs are actively managed, meaning a fund manager picks which securities to hold, trying to beat the index. These funds charge higher fees — often 0.50% to 1.00% or more per year — because you are paying for the manager's research and decisions. Over long periods, most actively managed funds do not beat their index counterparts after fees, so many investors stick with index ETFs.

For a beginner, index ETFs are usually the better choice. They are transparent (you know exactly what you own), they are cheap, and they work well for buy-and-hold investing. You can always move to actively managed funds later if you want to.

Broad market ETFs for a simple core portfolio

If you want to keep things simple and do not have strong opinions about which sectors or countries to favor, a portfolio of two or three broad index ETFs can work for decades. The most common approach is to hold a U.S. stock ETF, an international stock ETF, and a bond ETF, split according to your age and risk tolerance.

A U.S. stock ETF might track the S&P 500 (500 large U.S. companies), the total U.S. stock market (which includes mid-size and small companies too), or the Nasdaq-100 (100 large tech-heavy companies). The S&P 500 and total market versions are the most popular for long-term investors because they are broad and have very low fees — often 0.03% to 0.10% per year.

An international stock ETF gives you exposure to companies outside the U.S., usually in developed countries (Europe, Japan, Australia) or emerging markets (China, India, Brazil). This reduces the risk that your entire portfolio depends on U.S. economic performance. International ETFs typically cost 0.08% to 0.20% per year.

A bond ETF holds government or corporate bonds and provides steadier returns with less day-to-day price swings than stocks. A total bond market ETF holds thousands of bonds across different maturities and credit qualities. Bond ETFs usually cost 0.03% to 0.10% per year.

How to decide on a stock-to-bond split

The split between stocks and bonds depends on how long you can leave the money invested and how much you can tolerate seeing your account value drop in a bad year. Stocks are more volatile — they can fall 20%, 30%, or more in a single year — but they tend to grow faster over decades. Bonds are steadier but grow more slowly.

A common rule of thumb is to hold a percentage in bonds equal to your age (so a 30-year-old holds 30% bonds, 70% stocks) or to subtract your age from 110 (so a 30-year-old holds 80% stocks, 20% bonds). These are starting points, not rules. If you panic and sell when the market drops 20%, you probably need more bonds. If you have decades until you need the money and can ignore short-term swings, you might hold mostly stocks.

Another approach is to think about when you will need the money. If you will not touch it for 20+ years, stocks make sense for most of it. If you need some of it within 5 years, shift that portion into bonds or cash.

Sector and theme ETFs for focused bets

Beyond broad market ETFs, you can buy ETFs focused on specific industries (technology, healthcare, energy) or themes (renewable energy, artificial intelligence, dividend-paying stocks). These let you overweight areas you think will outperform or underweight areas you want to avoid.

Sector ETFs track groups of companies within the S&P 500 or other indexes. For example, a technology sector ETF holds the tech companies in the S&P 500. These are useful if you want more exposure to one industry than the broad market gives you, but they also concentrate your risk. If that sector struggles, your returns suffer.

Theme ETFs are newer and less standardized. They might hold companies involved in electric vehicles, cybersecurity, or space exploration. These can be interesting, but they often have higher fees (0.40% to 0.70% per year) and smaller asset bases, which can make them harder to trade. Use them as a small part of your portfolio, not the core.

International and emerging market ETFs

If you want more international exposure than a single developed-markets ETF provides, you can buy separate ETFs for specific regions or emerging markets. A developed international ETF might hold stocks from Europe, Japan, and Australia. An emerging markets ETF holds stocks from faster-growing but riskier countries like China, India, Brazil, and Mexico.

Emerging markets ETFs have higher expense ratios than developed-market ETFs — often 0.08% to 0.20% per year — because the markets are less liquid and harder to trade. They also tend to be more volatile. But over long periods, emerging markets have offered higher returns to compensate for that risk, though past performance does not may provide future results.

Many investors hold a mix: 60% to 70% U.S. stocks, 20% to 30% developed international stocks, and 5% to 10% emerging markets. This spreads risk across geographies without overweighting the riskier emerging markets.

Comparing fees and finding the right brokerage

Expense ratios vary widely, and small differences compound over time. An ETF charging 0.50% per year costs twice as much as one charging 0.25% per year. Over 30 years on a $100,000 investment, that difference can amount to tens of thousands of dollars in foregone returns.

Most major brokerages — Fidelity, Vanguard, Charles Schwab, E-Trade, and others — now offer commission-free trading on ETFs. That means you pay no fee to buy or sell. You only pay the ETF's expense ratio. Some brokerages also offer a selection of their own ETFs with very low fees (often 0.03% or less), which can save you money if you plan to hold them long-term.

Before you open an account, compare the expense ratios of the specific ETFs you want to buy across different brokerages. Sometimes one brokerage offers a cheaper version of a similar fund. Also check whether the brokerage charges account maintenance fees or minimum balance requirements — most do not, but some do.

Frequently Asked Questions

Can I lose all my money in an ETF?

No. An ETF holds many securities, so even if one company fails, you lose only a small fraction of your investment. The entire ETF would have to go to zero, which would mean every single holding failed simultaneously — extremely unlikely for a broad market ETF. Individual stocks can go to zero; diversified ETFs almost never do.

Should I buy individual stocks instead of ETFs?

If you enjoy researching companies and have time to monitor them, individual stocks can work. But most investors who pick individual stocks underperform the market after fees and taxes. ETFs let you own the whole market with minimal effort and cost. You can do both: hold a core portfolio of ETFs and use a small portion for individual stock picks.

How many ETFs should I own?

Three to five is typical for a simple portfolio: one U.S. stock ETF, one international stock ETF, one bond ETF, and maybe one or two sector or theme ETFs if you want focused exposure. More than that and you are likely duplicating holdings and paying unnecessary fees. Fewer than three and you might lack diversification.

Do I need to rebalance my ETF portfolio?

Yes, over time. If stocks outperform bonds, your stock allocation drifts higher and your portfolio becomes riskier than you intended. Rebalancing means selling some of what has grown and buying more of what has lagged, bringing your portfolio back to your target split. Most investors rebalance once a year or when allocations drift more than 5% from target.

What is the difference between an ETF and a mutual fund?

Both hold baskets of securities, but ETFs trade like stocks during market hours and usually have lower fees. Mutual funds trade once per day after the market closes and often charge more. For most investors, ETFs are the better choice today, though mutual funds still have a place for certain strategies.