Market concentration

This chart compares market concentration across three decades by visualizing the top 20 US 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 increasing concentration: in 1995, market value was more evenly distributed among top companies; by 2025, the largest companies command dramatically larger shares of total market capitalization, with the top few firms dominating the market landscape. 

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.