Why are index funds considered so tax-efficient?

Index funds, especially in ETF form, minimize the taxes you owe while you hold them. Because they simply track an index rather than actively trading, they have very low turnover – managers rarely sell holdings, so they generate few internal capital gains distributions to pass on to you. ETFs also use an in-kind redemption mechanism that lets them flush out low-basis shares without triggering taxable gains, which is why broad-market ETFs often distribute essentially zero capital gains year after year. Their dividends are mostly qualified, taxed at lower rates. Contrast that with actively managed funds, which can hand you a surprise taxable distribution even in a down year. For a taxable brokerage account, a low-cost total-market index fund or ETF is about as tax-friendly as a diversified stock holding gets. Build one at wealthserene.com/tools/portfolio-builder.