42 AI Stocks Generated 67% of S&P 500 Price Returns Since 2024

A group of 42 artificial intelligence stocks generated 67% of the S&P 500’s price returns since January 2024, concentrating much of the benchmark’s advance in a small set of companies.

The stocks contributed 22 percentage points of the index’s 33% gain during the period. The other 458 companies contributed 11 percentage points.

The concentration also extended to corporate performance and investment. The 42 companies accounted for 58% of S&P 500 earnings growth and 81% of combined capital expenditure and research-and-development growth. Much of that spending supports data centers, advanced semiconductors and computing infrastructure used to develop and operate artificial intelligence systems.

Only 29% of stocks outperformed the S&P 500 over the previous three years, indicating limited breadth beneath the index’s headline gains. The benchmark uses float-adjusted market-capitalization weighting, giving larger companies a greater influence on its performance.

A separate measure covering the period since ChatGPT launched in November 2022 found that 42 AI-related companies represented about 65% to 75% of S&P 500 earnings, revenues and capital spending. That comparison covers a longer period and uses different measurements from the January 2024 price-return analysis.

Recent corporate reporting also showed concentrated AI-related activity. Artificial intelligence appeared on 67% of S&P 500 earnings calls in the second quarter, while 10 companies accounted for 77% of expected second-quarter earnings growth in an August analysis.

The figures show how heavily the S&P 500’s returns, earnings expansion and spending growth have depended on AI-related companies. They do not establish whether current valuations are justified or indicate how the market will perform in the future.