An index fund is a type of mutual fund or ETF that tracks a market index — like the S&P 500 (500 largest US companies) or the total stock market. Instead of a manager picking stocks, it holds everything in the index, weighted by market cap.
Why Index Funds Usually Win
- •Low cost: Average index fund expense ratio: 0.03%–0.10%. Active funds: 0.5%–1.5%. Over 30 years, that 1% difference on $100,000 = $200,000+ in lost returns
- •Diversification: S&P 500 index = 500 companies across every sector. Instant diversification.
- •Performance: Over 15-year periods, ~80–90% of active managers underperform their benchmark index after fees
- •Tax efficiency: Low turnover means fewer taxable events than active funds
- •Simplicity: No research, no stock picking, no fund manager to evaluate
Most Popular Index Funds
- •VOO (Vanguard S&P 500 ETF): Tracks S&P 500, 0.03% expense ratio
- •FXAIX (Fidelity 500 Index): Same index as VOO, 0.015% expense ratio
- •VTI (Vanguard Total Stock Market): All US stocks, 0.03%
- •VT (Vanguard Total World): US + international, 0.07%
- •BND (Vanguard Total Bond Market): Bonds component, 0.03%
The expense ratio is the one fee you can't avoid in investing. Even 0.1% vs 1.0% costs you enormously over decades. Always check the expense ratio before buying any fund. There is no reason to pay more than 0.1%.
The simplest long-term portfolio: One index fund (VTI or VOO) for decades. That's it. You don't need more complexity than that to build significant wealth — and more complexity usually produces worse results.