An Exchange-traded Fund is a pooled fund that, like a mutual fund, holds a basket of underlying securities (usually tracking an index), but unlike a mutual fund trades intraday on a public exchange at a market-clearing price. The defining structural feature is the creation/redemption mechanism: large institutional players called authorized participants exchange ETF shares for the underlying basket in-kind, which is not a taxable event for the fund and never forces it to sell appreciated holdings. That single mechanism is why ETFs pass through essentially no embedded capital gains during their lifetime — a structural advantage that mutual funds cannot replicate.
The ETF universe spans every conceivable exposure: broad-index funds, smart-beta and factor products, sector and thematic funds, actively managed ETFs, and leveraged or inverse products that use derivatives to amplify or invert daily returns. For the investor-side material — selecting ETFs by expense ratio, types and risks, ETFs of ETFs, and the role ETFs play as the second-best wrapper below the direct-indexing minimums — see section “Exchange-Traded Funds (ETFs)”.