VTI vs VOO: Which One Is the Smarter Buy Today?

The Vanguard S&P 500 ETF (VOO) covers the U.S. large-cap market, while the Vanguard Total Stock Market ETF (VTI) includes virtually every investable stock. VTI's inclusion of mid- and small-cap stocks is the big differentiator, and it's weighed down performance over the past decade.