Index Fund
Definition
A fund that holds all (or most) of the stocks in a specific market index, like the S&P 500 or total stock market. The goal isn't to beat the market — it's to match it. Lower fees than actively managed funds because there's minimal trading and no manager trying to pick winners.
Why It Matters
Most professional investors can't beat the market consistently. Index funds are the proven way to participate in market growth without overpaying for management. Studies show 80-90% of actively managed funds underperform index funds over 15+ years.
Example
A total stock market index fund holds thousands of companies weighted by size. You're betting on the overall economy growing, which historically averages 10% annually before inflation.