The best S&P 500 index funds aren't just mutual funds and ETFs with multiple-decade track records. Many fund providers tweak the S&P 500 a bit for their purposes, whether to add more exposure to specific sectors or focus more on large or small-cap stocks. For example, the Vanguard S&P 500 Growth ETF (NYSE: VOOG) whittles down the S&P 500 to 233 stocks and focuses on the companies with the highest growth potential.
This ETF seeks growth, so naturally, the holdings are heavily weighted toward the tech sector. VOOG has 34% of its holdings in tech sector stocks compared to SPY's 27%. And while growth funds tend to bring in more than average volatility, an investment in the Vanguard S&P 500 Growth ETF has beaten the main S&P 500 index over the last five years.