Nvidia's huge stock rally is still exerting an outsized influence over the S&P 500 index , reinforcing concerns that broader markets could be hurt if the chipmaking giant's fortunes turn.

We've gotten used to Nvidia (NASDAQ: NVDA) reaching "firsts" or records -- the company repeatedly has launched the world's fastest artificial intelligence (AI) chip yet and reported its highest quarterly revenue ever. Nvidia's standout moments have been very positive. But in recent days, the situation hasn't been as bright.

Shares of NVIDIA Corp. NVDA shed 0.03% to $119.10 Friday, on what proved to be an all-around favorable trading session for the stock market, with the S&P 500 Index SPX rising 0.54% to 5,626.02 and the Dow Jones Industrial Average DJIA rising 0.