S&P 500 vs Total Stock Market Index

The S&P 500 tracks 500 large-cap U.S. companies and represents approximately 80% of U.S. market capitalization, while the Total Stock Market Index includes all publicly traded U.S. stocks (approximately 3,500+ companies) across all market capitalizations. The S&P 500 is more concentrated in mega-cap tech stocks, whereas the Total Stock Market provides broader diversification including mid-cap and small-cap exposure.