Before we proceed, let us understand the key learnings from this chapter.

• The S&P 500 is the key US benchmark. It tracks 503 large companies, representing about 80% of the US market and roughly $62 trillion in value (2026). 
• The Dow Jones is historically important but limited. It tracks 30 companies using price weighting, meaning stock splits can significantly change index weights. 
• NASDAQ indexes capture the tech-heavy market. The NASDAQ Composite includes 3,000+ companies, while the NASDAQ-100 tracks the largest non-financial firms and is about 60% technology. 
• Russell indexes track the broader market. The Russell 3000 covers 98% of US equities, with the Russell 1000 for large caps and Russell 2000 for small caps. 
• Returns can include sharp volatility. The S&P 500 returned 16.4% in 2025, despite a 10.6% two-day crash in April before recovering. 
• Market concentration has increased sharply. The top ten companies now make up 40.7% of the index, up from 19% in 1990. 

Owning the S&P 500 today means strong exposure to technology and AI leaders.