Index Funds: The Simple Path to Wealth

Updated April 2026 · 11 min read

Quick Answer

An index fund is a mutual fund or ETF that tracks a market index like the S&P 500. Warren Buffett, Jack Bogle, and most financial experts agree: for the vast majority of investors, a low-cost S&P 500 index fund is the single best investment you can make. Fees as low as 0.03%.

Why Index Funds Win

The evidence is overwhelming: over 90% of actively managed funds fail to beat their benchmark index over 15-year periods. After accounting for higher fees, active managers destroy wealth rather than create it for most investors.

Index funds win because of three factors: low fees (0.03% vs 1%+), broad diversification (500+ stocks), and tax efficiency (minimal trading means fewer taxable events).

How Index Funds Work

An S&P 500 index fund buys all 500 stocks in the S&P 500 in proportion to their market capitalization. Apple makes up ~7% of the index, so ~7% of the fund is Apple. When the index changes (companies are added/removed), the fund adjusts automatically.

The Three-Fund Portfolio

One of the most popular strategies for index fund investors:

  1. US Total Stock Market — VTI or VTSAX (60-80%)
  2. International Stock Market — VXUS or VTIAX (15-30%)
  3. US Total Bond Market — BND or VBTLX (5-30%)

Adjust percentages based on your age and risk tolerance. Use our portfolio allocation tool to find your ideal mix.

Top Index Funds

  • VOO / VFIAX — S&P 500 (0.03% / 0.04%)
  • VTI / VTSAX — Total US Stock Market (0.03% / 0.04%)
  • VXUS / VTIAX — Total International (0.07% / 0.11%)
  • BND / VBTLX — Total Bond Market (0.03% / 0.05%)
  • FXAIX — Fidelity S&P 500 (0.015%) — one of the cheapest anywhere
  • FZROX — Fidelity ZERO Total Market (0.00%) — literally free

Related

Frequently Asked Questions

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