$SPY vs $VTI: Weighing the Trade-offs Between These Popular U.S. Equity ETFs SPDR S&P 500 ETF Trust (SPY) tracks the S&P 500 Index with approximately 505 large-cap holdings, while Vanguard Total Stock Market ETF (VTI) follows the CRSP US Total Market Index with over 3,500 holdings spanning large-, mid-, and small-cap segments. SPY maintains higher concentration in mega-cap technology names, resulting in greater sector exposure to Information Technology at around 38%, compared to VTI's slightly broader but still technology-heavy allocation.