Investor Education
How ETFs Work
ETFs have transformed investing — they give you instant diversification, low costs, and the flexibility to trade like a stock. Here's everything you need to know about how they're built, how they trade, and how to pick the right ones.
In This Guide
- 1. What Is an ETF?
- 2. ETFs vs. Mutual Funds vs. Index Funds
- 3. How ETF Creation and Redemption Works
- 4. Types of ETFs
- 5. Understanding Expense Ratios
- 6. How to Read an ETF's Key Metrics
- 7. Passive vs. Active ETFs
- 8. Covered Call ETFs (JEPI, XYLD)
- 9. Leveraged and Inverse ETFs
- 10. ETF Glossary
1. What Is an ETF?
An ETF (Exchange-Traded Fund) is a basket of securities — stocks, bonds, commodities, or a mix — packaged into a single investment that trades on a stock exchange just like a share of Apple or Tesla. When you buy one share of SPY, you're effectively buying a tiny slice of all 500 companies in the S&P 500 simultaneously.
ETFs were invented in 1993 when State Street launched SPY — still the world's largest ETF with over $500 billion in assets. The structure solved a fundamental problem with mutual funds: you couldn't trade them intraday, they often came with high fees, and they frequently distributed taxable capital gains to shareholders. ETFs fixed all three.
Key Insight
The ETF industry now holds over $10 trillion in assets globally. For most retail investors, a simple two-ETF portfolio (a broad U.S. equity ETF + a bond ETF) will outperform the vast majority of actively managed strategies over a 20-year horizon.
2. ETFs vs. Mutual Funds vs. Index Funds
| Feature | ETF | Mutual Fund | Index Fund |
|---|---|---|---|
| Trades like a stock | Yes — intraday | No — end of day NAV | No — end of day NAV |
| Minimum investment | One share (~$50–$500) | Often $1,000–$3,000 | Often $1–$3,000 |
| Expense ratio | 0.03%–0.75% typical | 0.5%–1.5% typical | 0.03%–0.20% typical |
| Tax efficiency | Very high (in-kind redemption) | Lower (capital gains distributions) | Moderate to high |
| Transparency | Daily holdings disclosure | Quarterly disclosure | Daily (if ETF structure) |
| Active management option | Yes (active ETFs exist) | Yes | No — tracks an index |
The terms "ETF" and "index fund" are often used interchangeably but they're not the same thing. An index fund is a strategy (tracking an index passively). An ETF is a structure (trades on an exchange). Most ETFs are index funds, but not all index funds are ETFs — Vanguard's VTSAX, for example, is an index mutual fund, not an ETF.
3. How ETF Creation and Redemption Works
ETFs use a unique "creation/redemption" mechanism that keeps their market price close to their net asset value (NAV) and makes them extremely tax-efficient. Here's how it works:
Large institutional investors called "authorized participants" (APs) can create new ETF shares by delivering a basket of the underlying securities to the ETF issuer, who then issues new ETF shares in return. They can also redeem ETF shares by returning them to the issuer in exchange for the underlying securities. This in-kind exchange means the ETF rarely has to sell securities for cash — which is what triggers capital gains distributions in mutual funds.
When an ETF trades at a premium to its NAV (market price above the value of its holdings), APs create new shares to arbitrage the difference. When it trades at a discount, they redeem shares. This arbitrage mechanism is why most ETFs trade very close to their NAV throughout the day.
4. Types of ETFs
| Type | What It Holds | Examples | Best For |
|---|---|---|---|
| Broad Market | All U.S. stocks or S&P 500 | VTI, SPY, IVV, VOO | Core long-term holding |
| Sector | One industry (tech, energy, healthcare) | XLK, XLE, XLV, XLF | Tactical sector tilts |
| International | Non-U.S. stocks | EFA, VEA, EEM, VWO | Geographic diversification |
| Bond | Government or corporate bonds | AGG, BND, TLT, HYG | Income and stability |
| Commodity | Gold, oil, agriculture | GLD, SLV, USO, DJP | Inflation hedge |
| Covered Call | Stocks + options income strategy | JEPI, JEPQ, XYLD | High income in sideways markets |
| Leveraged | 2x or 3x daily index returns | TQQQ, SOXL, UPRO | Short-term speculation only |
| Inverse | Profits when index falls | SH, PSQ, SQQQ | Hedging, short-term only |
| Crypto | Bitcoin or Ethereum exposure | IBIT, FBTC, ETHA | Crypto exposure without wallets |
5. Understanding Expense Ratios
The expense ratio is the annual fee an ETF charges, expressed as a percentage of assets. It's deducted automatically from the fund's returns — you never write a check for it. A 0.03% expense ratio on a $10,000 investment costs you $3 per year. A 0.75% expense ratio costs you $75. Over 30 years with 8% annual returns, that difference compounds to a meaningful sum.
| ETF Category | Typical Expense Ratio | Example |
|---|---|---|
| Broad U.S. Index | 0.03%–0.05% | VOO (0.03%), IVV (0.03%) |
| International Index | 0.05%–0.15% | VEA (0.06%), EFA (0.32%) |
| Sector ETF | 0.10%–0.20% | XLK (0.10%), XLE (0.10%) |
| Bond ETF | 0.03%–0.15% | BND (0.03%), AGG (0.03%) |
| Covered Call ETF | 0.35%–0.60% | JEPI (0.35%), XYLD (0.60%) |
| Active ETF | 0.40%–0.75% | ARKK (0.75%), QQQM (0.15%) |
| Leveraged ETF | 0.75%–1.00% | TQQQ (0.88%), SOXL (0.75%) |
6. How to Read an ETF's Key Metrics
Before buying any ETF, check these five metrics on the fund's fact sheet or on a site like ETF.com or Morningstar:
AUM (Assets Under Management)
Total assets in the fund. Larger AUM generally means tighter bid-ask spreads and lower trading costs. Avoid ETFs with under $100M AUM — they risk closure.
Average Daily Volume
How many shares trade per day. Higher volume = easier to buy and sell without moving the price. Low-volume ETFs can have wide bid-ask spreads.
Bid-Ask Spread
The difference between the buy price and sell price. A wide spread is a hidden cost. For liquid ETFs like SPY, the spread is often just $0.01.
Tracking Error
How closely the ETF follows its benchmark index. A fund tracking the S&P 500 should return almost exactly what the S&P 500 returns, minus the expense ratio.
Distribution Yield
The annualized income the ETF pays out as a percentage of its price. Includes dividends and, for covered call ETFs, options premium income.
7. Passive vs. Active ETFs
The vast majority of ETF assets are in passive index-tracking funds. But active ETFs — where a portfolio manager makes discretionary investment decisions — have grown rapidly since the SEC changed rules in 2019 to make them easier to launch.
The evidence on active ETFs is mixed. ARK Invest's ARKK became famous for its 150% return in 2020, then lost 75% from its peak by 2022. JPMorgan's JEPI has been a genuine success story — delivering consistent monthly income with lower volatility than the S&P 500. The key question for any active ETF: does the manager's edge justify the higher expense ratio?
8. Covered Call ETFs (JEPI, XYLD)
Covered call ETFs hold a portfolio of stocks and simultaneously sell call options on those stocks (or on an index). The options premium collected is distributed to shareholders as monthly income, producing yields of 7–12% annually. The tradeoff: by selling the upside above the strike price, these funds cap their gains in strong bull markets.
JEPI (JPMorgan Equity Premium Income ETF) is the most popular covered call ETF with over $35 billion in assets. It uses ELNs (Equity-Linked Notes) rather than direct options, giving it more flexibility to generate income while maintaining a lower-volatility equity portfolio. Its 12-month distribution yield is approximately 7.5% as of early 2026.
Watch Out
Covered call ETF distributions are not guaranteed and fluctuate with options market conditions. In low-volatility environments, the premium collected — and therefore the yield — decreases. These are income tools, not total return vehicles.
9. Leveraged and Inverse ETFs
Leveraged ETFs use derivatives to deliver 2x or 3x the daily return of an index. TQQQ, for example, aims to return 3x the daily performance of the Nasdaq 100. If the Nasdaq rises 1% on Monday, TQQQ should rise roughly 3%. If it falls 1%, TQQQ falls roughly 3%.
The critical caveat: leveraged ETFs reset daily. Due to "volatility decay" (also called beta slippage), holding a leveraged ETF through a volatile period produces returns significantly worse than 3x the index return over that period. A 10% drop followed by a 10% recovery leaves the index flat but leaves a 3x leveraged ETF down about 9%. These are short-term trading instruments, not long-term investments.
High Risk Warning
Leveraged and inverse ETFs are designed for experienced traders using them for short-term hedging or speculation. Holding them for weeks or months in a volatile market can result in losses far exceeding the underlying index's move. They are not suitable for buy-and-hold investors.
10. ETF Glossary
NAV (Net Asset Value)
The per-share value of an ETF's underlying holdings. ETF market price should trade close to NAV.
Authorized Participant (AP)
Large institutional investors who create and redeem ETF shares in bulk to keep prices aligned with NAV.
Expense Ratio
The annual fee charged by an ETF, expressed as a percentage of assets. Automatically deducted from returns.
Bid-Ask Spread
The difference between the highest price a buyer will pay and the lowest price a seller will accept.
Tracking Error
The deviation between an ETF's returns and its benchmark index returns.
Distribution Yield
Annualized income paid out by an ETF as a percentage of its current price.
ELN (Equity-Linked Note)
A structured product used by JEPI to generate options-like income without directly selling options.
Beta Slippage
The compounding effect that causes leveraged ETFs to underperform their stated multiple over time in volatile markets.
AUM (Assets Under Management)
Total dollar value of assets held in an ETF. Larger AUM generally means better liquidity.
In-Kind Redemption
The ETF mechanism where shares are exchanged for the underlying securities (not cash), avoiding capital gains taxes.
Premium/Discount
When an ETF trades above (premium) or below (discount) its NAV. Arbitrage by APs keeps this gap small for liquid ETFs.
Rebalancing
The periodic adjustment of an index's composition — when a stock is added or removed from the S&P 500, ETFs tracking it must buy or sell accordingly.