An exchange-traded fund, or ETF, pools money from investors and holds a portfolio that may contain stocks, bonds or other assets. Shares of ETFs trade on stock exchanges, so investors can generally buy and sell them through brokerage accounts while the market is open.
What you own when you buy an ETF
Each ETF share represents an interest in the fund’s portfolio and the income it generates. ETFs vary greatly: some track broad market indexes, while others focus narrowly on an industry, country, strategy or even a single stock.
Diversification can be a benefit—but is not automatic
A broad ETF can provide exposure to many securities through one investment. A narrowly focused ETF may provide little diversification, so investors should examine the fund’s objective and holdings rather than assuming every ETF is diversified.
ETF prices and net asset value
ETF shares trade at market prices. Those prices can be above or below the fund’s net asset value, or NAV. The difference is called a premium or discount.
Costs matter
Investors should review the fund’s expense ratio as well as potential brokerage, bid-ask spread and other trading costs. Even small recurring costs can affect long-term results.
What to review before investing
Read the ETF’s prospectus and shareholder information. Understand what the fund owns, how its strategy works, its risks, fees and whether it fits your broader financial situation and portfolio.
Educational note: This article is for general educational purposes and does not provide individualized investment, tax, or legal advice. Investing involves risk, including possible loss of principal.
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Published: September 6, 2026 Updated: September 6, 2026
Reviewed by: Allocate Yourself Editorial Team Last reviewed: 2026-09-06