Exchange-Traded Fund (ETF)

An ETF bundles many individual securities — stocks, bonds, commodities, or combinations — into a single tradable unit. Investors buy and sell shares of that unit on an exchange at prices that fluctuate in real time, unlike a traditional mutual fund, which prices only once at the end of each trading day. This continuous pricing gives ETFs a liquidity profile that many wealthy families find useful for managing large, complex portfolios.

ETFs are often associated with passive investing because many track a published index, but actively managed ETFs also exist. The structure itself is simply a wrapper — the investment approach inside can vary widely. A hypothetical family office managing a diversified public-markets portfolio might use ETFs for rapid, low-friction exposure to a broad asset class while longer-term positions are being constructed through separately managed accounts or direct indexing.

A common confusion is treating "ETF" and "index fund" as synonyms. Index funds can take many legal forms; an ETF is a specific structural form that can hold either indexed or actively managed strategies. Another frequent misunderstanding involves the ETF's two layers of cost: the fund's internal expense ratio and any brokerage commissions or bid-ask spread paid when trading shares. Both matter when evaluating total cost. For a broader view of where ETFs fit, see public markets overview and exchange-traded funds.