The seven companies that make up the S&P 500's "Magnificent Seven" stocks have been on the rise for some time.
Two years ago, they combined to account for 30% of the total valuation of the S&P 500 (Index: SPX). And to be sure, several of the members of this elite group of high-flying companies were already among the biggest components of the index before they became collectively known as the "Magnificent 7". The weren't known by that label until 2023, when Bank of American analyst Michael Hartnett first deployed the phrase with respect to "a basket of seven stocks: Alphabet (GOOG, GOOGL), Amazon (AMZN), Apple (AAPL), Meta Platforms (META), Microsoft (MSFT), Nvidia (NVDA) and Tesla (TSLA)".
Since then, these mega-cap stocks have earned the moniker by growing even larger. Through October 2025, they have collectively grown to account for 37% of the entire market capitalization of the S&P 500.
Pretty amazing stuff when you realize that Tesla wasn't even a publicly-traded company until 2010 and Nvidia's explosive growth because of its Artificial Intelligence (AI) enabling computer chip technology began in 2023.
The following pair of charts illustrate the growth of the Magnificent Seven stocks over the past two years. The first chart shows how their value has increased and driven the growth of the S&P 500 index itself. The second chart shows how their collective share of the S&P 500 index has likewise grown.
They're able to drive the total valuation of the S&P 500 because their market capitalizations make up such a large share of the index. In today's market, what happens to the S&P 500 index is almost all about what's happening with the Magnificent Seven stocks.
How long might that last? Time will tell, but it helps put today's record concentration of market capitalization by seven companies into some context, the last time the S&P 500 index (or rather, its predecessor index, the S&P 90) had such a large percentage of its total value represented by such a small number of stocks was back in 1932.
References
Follow the links for the tickers of the Magnificent Seven stocks we posted in the article to our sources for their market capitalization. Meanwhile, here's our source for the S&P 500's monthly market capitalization:
Standard and Poor. S&P Market Attributes Web File. [Excel Spreadsheet]. Accessed 3 November 2025.
Image Credit: Microsoft Copilot Designer. Prompt: "A picture of a large electronic screen showing the tickers NVDA, AAPL, MSFT, GOOG, AMZN, META, and TSLA, and the words 'MAGNIFICENT 7'".