SCHB tracks the Dow Jones U.S. Broad Stock Market Index, which covers almost the entire US equity market, thousands of stocks from large caps to small caps, weighted by market capitalization. Because of cap weighting, the largest companies dominate the portfolio, and returns have been close to those of the S&P 500 over long periods. SCHB is very similar to VTI and ITOT and differs mainly in the index provider and in small details of composition.