Nvidia, Apple, and Microsoft are keeping the stock market afloat

The stock market is pretty much being kept afloat by three tech stocks .

The S&P 500 ( ^GSPC ) has never been more concentrated in just three stocks than it is today, with Nvidia ( NVDA ), Apple ( AAPL ), and Microsoft ( MSFT ) representing over 21% of the index, per data from Creative Planning.

The importance of these three stocks to the S&P 500 has never been greater. Only IBM ( IBM ), AT&T ( T ), and ExxonMobil ( XOM ) could hold a candle to the three tech stalwarts of today: In the mid-1980s, those three industrial giants at their peak made up 13.4% of the S&P 500.

Nvidia, Apple, and Microsoft have been enjoying higher stock prices over the past month on the back of favorable news, pushing their concentration in the S&P 500 to a record.

The king of AI chips, Nvidia, revealed a stunning new $150 billion stock buyback plan two weeks ago — the largest share repurchase authorization increase in history. It brings the company's total buyback authorization to $235 billion. Shares are now hovering at a record high.

Apple's stock is also trading near a record high. The stock has been on a sizzling run since the company's product unveiling in mid-September.

Apple introduced the iPhone Duo, a device that features a passport-like design that opens and closes like a book. It sports a 5.4-inch front display that expands to a massive 7.6-inch display when opened, ideal for watching movies, playing games, working, and multitasking.

It also unveiled the new iPhone 18 suite and updated AirPods.

Microsoft's stock has also charged ahead, despite arguably lacking the robust recent news flow seen with Nvidia and Apple.

Wall Street analysts have been raising earnings estimates for Microsoft this year and next, citing expectations that AI demand will fuel strong Azure cloud sales.

Brian Sozzi is Yahoo Finance's Executive Editor, host of the Sozzi Unleashed morning show and the Power Players with Brian Sozzi podcast, and a member of Yahoo Finance's editorial leadership team. Follow Sozzi on X @BrianSozzi , Instagram , and LinkedIn . Tips on stories? Email brian.sozzi@yahoofinance.com.