This chart compares market concentration across three decades by visualizing the top 20 U.S. listed companies by market capitalization. Each horizontal rectangle represents one company, with area proportional to its market cap. The left half shows 1995; the right half shows 2025. The visualization reveals rising concentration: in 1995, market value was more evenly distributed among top companies; by 2025, market capitalization is increasingly concentrated in the largest firms.

Data: Top 20 S&P 500 companies by market capitalization for December 1995 and January 2025. Areas scaled proportionally within each year's total top-20 market cap.