What is a three-fund portfolio and why do people recommend it?

A three-fund portfolio holds just three low-cost index funds: a total U.S. stock market fund, a total international stock fund, and a total bond market fund. That's it. With those three you own thousands of companies worldwide plus a bond anchor, fully diversified, at rock-bottom expense ratios — often under 0.10%. It's popular because it's simple to manage, hard to mess up, and historically beats most actively managed and overly complex portfolios after fees. You control risk by adjusting the bond percentage and your domestic/international split (commonly 60–80% of stocks in U.S., the rest international). There's no stock-picking, no market timing, and rebalancing takes minutes once or twice a year. It's the default for many DIY investors precisely because boring, broad, and cheap tends to win over decades.