This year's 140% surge in shares of Nvidia, whose chips are seen as the gold standard in artificial intelligence applications, has accounted for about a quarter of the S&P 500's 17% gain.

Nvidia showed its powerful hold over Wall Street on Wednesday, when the stock's 8.2% rally helped drive the S&P 500 to its biggest intraday upswing in nearly two years. The index reversed a 1.6% loss to end the day up 1.1%.

Nvidia jumped after Chief Executive Officer Jensen Huang flagged strong demand for the company's chips, boosting its market value by more than $200 billion and accounting for 44% of the S&P 500's surge that day, data from Nomura showed.

Nvidia's rally "got the whole market moving," said Chris Murphy, co-head of derivative strategy at Susquehanna Financial Group.

The S&P 500 has struggled to make headway this year on Nvidia's down days, eking out gains only 13% of the time when the chipmaker's shares have closed weaker, a Reuters analysis showed.

--Reuters--