S&P 500 Concentration Is at a 50-Year High

What We're Showing

By early 2025, the top ten companies in the S&P 500 made up nearly 40% of the index—surpassing even the peak levels seen during the dot-com bubble.

This graphic, created in partnership with Tema ETFs and based on Bloomberg data, visualizes the rising concentration of the largest stocks within the S&P 500 over time.

Key Takeaways

• The S&P 500 is weighted by market capitalization, meaning the largest companies carry more influence.
• While strong performance from a few giants isn't necessarily bad, it does create concentration risk.
• The dominance of the top ten stocks has grown steadily over the past few decades—in 1990, they made up about 20% of the index versus 40% today.