The S&P 500 is more dependent on three stocks than ever before. Nvidia, Apple and Microsoft now together account for more than 21% of the S&P 500, according to data from Creative Planning.
This means a very large part of the index's performance is tied to just these three technology companies. Their combined weight in the S&P 500 has reached a record level, showing how concentrated the US stock market has become.
S&P 500 concentration hits record
Nvidia, Apple and Microsoft are now far more important to the index than the biggest companies were in previous decades. The only comparable example came in the mid-1980s, when IBM, AT&T and ExxonMobil together accounted for 13.4% of the S&P 500, according to the data cited by Yahoo Finance.
The current concentration is therefore significantly higher than the previous major example. Nvidia, Apple and Microsoft's combined share has crossed 21%, compared with 13.4% for IBM, AT&T and ExxonMobil at their peak in the 1980s.
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Nvidia stock hits record
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Nvidia stock hits record
{{/usCountry}}The three stocks have gained strongly over the past month. Favorable company news and rising share prices have pushed their combined weight in the S&P 500 to this record level, Yahoo Finance reported.
Nvidia has been one of the biggest drivers of the recent rise. The company, which dominates the market for AI chips, recently announced a $150 billion stock buyback plan. The $150 billion buyback authorization is the largest single increase in a share repurchase authorization in history, Yahoo Finance reported. The new plan takes Nvidia's total authorized buybacks to $235 billion.
Nvidia's stock has also climbed to record levels. Its rising share price has increased the company's weight in the S&P 500 and added to the index's dependence on the chipmaker.
Apple stock near record
Apple has also been trading close to a record high. Its stock has risen sharply since the company's product event in mid-September, helping increase Apple's influence on the S&P 500. Apple recently introduced the iPhone Duo, a foldable smartphone. The device has a 5.4-inch front display that opens like a book into a 7.6-inch screen, according to Yahoo Finance.
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The larger display is designed for activities such as watching movies, playing games, working and multitasking. Apple also introduced its iPhone 18 lineup and updated AirPods at the same product event, Yahoo Finance reported.
Microsoft stock rises
Microsoft has also seen its stock move higher, even without the same level of recent product news as Nvidia and Apple. The company's rising share price has also helped push the combined weight of the three companies higher.
Wall Street analysts have been increasing their earnings estimates for Microsoft for this year and next. Analysts expect continued demand for artificial intelligence to support strong sales from Microsoft's Azure cloud business, according to Yahoo Finance.
Three stocks drive S&P 500
The result is an unusually concentrated S&P 500. Nvidia, Apple and Microsoft now make up more than one-fifth of the entire index, meaning movements in these three stocks can have a major impact on the broader US stock market.
The record concentration also shows how strongly technology and AI-related companies now influence the US stock market. The S&P 500's performance is increasingly being shaped by the gains or losses of a small group of mega-cap technology companies.