What Are Stock Indexes?

Keeping Score

When you hear "the market was up today," what does that actually mean? There are thousands of stocks — they can't all move the same way. The answer is indexes — groupings of stocks used to measure the market as a whole.

The Big Three

S&P 500

The S&P 500 tracks 500 of the largest U.S. companies across every major sector. It's considered the best single measure of the U.S. stock market. When a news anchor says "the market gained 1% today," they usually mean the S&P 500.

Dow Jones Industrial Average

The Dow tracks only 30 large U.S. companies — older names like Coca-Cola, Boeing, and McDonald's. It's the oldest index (started in 1896) but narrower and less representative than the S&P 500.

Nasdaq Composite

The Nasdaq tracks thousands of stocks listed on the Nasdaq exchange, but it's dominated by tech giants like Apple, Microsoft, and NVIDIA. When tech is hot, the Nasdaq soars. When tech crashes, it drops hardest.

Why Indexes Matter

• Benchmarking: You can compare your portfolio's performance to "the market"
• Economic signal: A rising market usually reflects a growing economy
• Sector clues: Compare the Nasdaq vs S&P 500 to see if tech is outperforming
• Index funds: Many investors buy ETFs that simply track these indexes (like SPY or QQQ)

For FSL Players

Think of the indexes as your competition. If the S&P 500 is up 5% this month and your team is up 8%, you're beating the market. If the market is up 5% and your team is up 2%, you're technically gaining money — but underperforming.

A smart FSL goal isn't just "go up" — it's "beat the S&P 500."