What Is An ETF? Index Funds Vs ETFs Explained
How exchange-traded funds work and why they are popular with beginners.
Updated October 7, 2026 · 3 min read
In Short
An ETF (exchange-traded fund) is a basket of securities — stocks, bonds, or commodities — that trades on a stock exchange just like a single share. When you buy one share of an ETF like SPY, you instantly own a tiny slice of all 500 companies in the S&P 500.
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What Is An ETF?
ETFs were created so everyday investors could own a diversified portfolio without picking individual stocks. Today there are over 8,000 ETFs covering every market, sector, and strategy imaginable.
ETF Vs Mutual Fund Vs Individual Stock
| Feature | ETF | Mutual Fund | Individual Stock |
|---|---|---|---|
| Trades like | A stock (any time) | Once per day at close | A stock (any time) |
| Diversification | Built-in | Built-in | None |
| Typical fees | 0.03% - 0.75% | 0.5% - 1.5% | $0 commissions |
| Minimum investment | 1 share (or $1 with fractional) | Often $1,000+ | 1 share |
| Tax efficiency | High | Lower | Depends on trading |
What Is An Expense Ratio?
The expense ratio is the annual fee an ETF charges as a percentage of your investment. It is deducted automatically — you never see a bill.
Example: SPY has a 0.0945% expense ratio. On $10,000 invested, you pay roughly $9.45 per year. A managed mutual fund at 1% costs $100 on the same amount.
Index ETFs — those that track a market index like the S&P 500 — have the lowest fees because no one is actively picking stocks.
Types Of ETFs
| Type | What it tracks | Example |
|---|---|---|
| Broad market | Entire U.S. stock market | VTI, ITOT |
| S&P 500 | 500 largest U.S. companies | SPY, VOO, IVV |
| NASDAQ / tech | Top 100 NASDAQ stocks | QQQ, ONEQ |
| Sector | One sector only (tech, energy, etc.) | XLK, XLE, XLF |
| International | Non-U.S. markets | VEA, EEM |
| Bond | Government or corporate bonds | BND, TLT |
ETF Vs Index Fund — What Is The Difference?
The terms are often used interchangeably. Technically:
- An index fund is a mutual fund that tracks an index (traded once per day).
- An index ETF tracks the same index but trades intraday like a stock.
For most beginners, both are excellent low-cost options. ETFs are slightly more flexible; index mutual funds sometimes have no minimum investment when bought through a broker like Fidelity.
Why Do Beginners Love ETFs?
- Instant diversification — one purchase spreads risk across dozens or hundreds of stocks.
- Low cost — index ETFs charge 0.03-0.10% vs 1%+ for managed funds.
- Easy to buy — any brokerage account can buy ETFs like stocks.
- Transparency — you always know exactly what an ETF holds.
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Frequently Asked Questions
What is an ETF?
An ETF (exchange-traded fund) is a basket of securities — stocks, bonds, or commodities — that trades on a stock exchange just like a single share. Buying one ETF share gives you instant exposure to all the underlying holdings.
What is the difference between an ETF and an index fund?
Both track an index. The key difference: an index ETF trades intraday like a stock, while a traditional index mutual fund only prices once per day at market close. For most investors the two are functionally equivalent.
What is an expense ratio?
The expense ratio is the annual fee an ETF charges as a percentage of your investment, deducted automatically. SPY charges 0.0945% — about $9.45 per year on a $10,000 investment.
What are the best ETFs for beginners?
SPY and VOO (S&P 500), QQQ (NASDAQ 100), and VTI (total U.S. market) are among the most popular. They offer broad diversification at very low cost.
Can you lose money in an ETF?
Yes. If the underlying holdings fall in value, the ETF falls too. However, broad index ETFs have historically recovered from every downturn over long enough holding periods.