ETF vs. Mutual Fund

ETFs (exchange-traded funds) and mutual funds are two different wrappers around what can be an identical underlying portfolio. Many fund families offer the very same index strategy in both forms. The differences lie in how you buy and sell them, how they are taxed, and a few practical details — not usually in what they hold.

The most visible difference is trading. An ETF trades on an exchange throughout the day like a stock, so its price updates continuously and you can buy or sell any time the market is open, sometimes with commission-free access to fractional shares. A mutual fund transacts only once per day at its net asset value, calculated after the market closes. For a long-term allocator this rarely matters, but it gives ETFs more flexibility for anyone who cares about intraday pricing.

The more consequential difference is tax efficiency in taxable accounts. Thanks to an in-kind creation-and-redemption mechanism, ETFs can usually avoid passing capital-gains distributions to shareholders, whereas mutual funds sometimes distribute taxable gains even to investors who simply held on. In a tax-advantaged account like an IRA or 401(k), this distinction disappears and the two are essentially interchangeable.

Both structures can be extremely cheap index funds, so compare the expense ratio and tracking error directly rather than assuming one wrapper is always cheaper. This site catalogs ETFs specifically because they are the most common, flexible, and tax-efficient way for individual investors to implement the asset-allocation strategies shown here — but in most cases an equivalent mutual fund would build the same portfolio.