S&P 500 futures are little changed after index briefly tops 5,500: Live updates

S&P 500 futures ticked up marginally on Friday morning after the broad market benchmark briefly climbed above 5,500 for the first time.

S&P 500 futures inched higher by 0.09%, while futures tied to the Dow Jones Industrial Average added 6 points, or 0.02%. Nasdaq 100 futures advanced 0.23%.

In Thursday's regular session, the S&P 500 closed 0.25% lower. At its highs of the day, the broad market index was up by as much as 0.34%, reaching 5,505.53. The Nasdaq Composite fell 0.79%, also after hitting an all-time high earlier in the day. The 30-stock Dow was the outlier of the three major averages, rising nearly 300 points, or 0.77%, for its best day this month.

Nvidia fell 3.5% on Thursday, leading the information technology sector to drop 1.6%. Nonetheless, the chipmaker is still up more than 160% year to date, and it briefly beat Microsoft as the most valuable public company on Tuesday.

While some signs of an overextended market are appearing, it isn't clear yet whether the market has reached its limits on the artificial intelligence-fueled rally — which can't continue its "meteoric rise," said Jamie Cox, managing partner at Harris Financial Group. 

"The good news is, reality does not mean markets crashing or having these big, massive draw downs," he said. "It's more of a rebalancing of the field a little bit, because the valuations of those companies have just gotten so far afield from the average stock that you probably would see some broadening, which has been long talked about." 

As of Thursday's close all three major averages are on pace for weekly gains. The S&P 500 is tracking for a roughly 0.8% advance, while the Nasdaq is up 0.2%. The Dow is the outperformer, touting a 1.4% rise week to date.

On Friday, investors will be