What's the smartest number of ETFs to hold to be diversified without overlap?

You can be fully diversified with remarkably few funds. A classic simple portfolio uses just three: a total U.S. stock market fund, a total international stock market fund, and a total bond market fund, adjusting the mix to your risk tolerance. Some investors use even one all-in-one fund. Holding a dozen overlapping ETFs doesn't add diversification if they own many of the same companies; it just creates complexity and makes rebalancing harder. Before adding a fund, ask what genuinely new exposure it provides. More funds also mean more tickers to track for taxes and rebalancing. Aim for the fewest broad, low-cost funds that cover U.S. stocks, international stocks, and bonds. You can explore ready-made mixes with WealthSerene's tool at wealthserene.com/tools/model-portfolios.