Back to Blog
investing 2026-04-21

Index Funds Explained

Why low-cost index funds outperform most active managers over decades.

Index funds buy every stock in an index proportionally.

How They Work

A fund tracking the S&P 500 holds all 500 stocks weighted by market cap.

Why Costs Matter

A 1% fee compounds over 30 years at 7% returns:

  • 0.04% expense ratio (VTI)
  • 1.0% expense ratio
  • Difference: roughly 22% of final wealth

Common Indices

  • S&P 500
  • Total US Market (VTI)
  • MSCI EAFE
  • Emerging Markets
  • Total Bond Market

Three-Fund Portfolio

`` 60% Total US Stock Market 30% Total International 10% Total Bond Market ``

ETF vs Mutual Fund

Both offer index exposure. ETFs usually more tax-efficient in taxable accounts.

Common Mistakes

  • Picking too many funds (overlap)
  • Tracking errors
  • Leveraged or inverse ETFs
  • Selling during downturns
Educational only. Not financial advice.