In early trading hours on December 23 (Beijing time), U.S. stocks maintained their upward momentum in Monday's late session, with the technology sector leading the gains. Trading hours this week will be shortened due to the Christmas holiday. Traders are assessing whether tech stocks can regain their upward trajectory before year-end.

The Dow Jones Industrial Average rose 248.45 points, or 0.52%, to 48,383.34. The Nasdaq Composite gained 118.85 points, or 0.51%, closing at 23,426.47. The S&P 500 added 41.53 points, or 0.61%, ending at 6,876.03.

U.S. markets will close early at 1:00 p.m. ET on Wednesday and remain closed on Thursday for Christmas Day.

Key AI-related stocks broadly advanced following reports that Nvidia is pushing to export its H200 chips by mid-February. The news lifted shares of Micron Technology and Oracle, among other AI-focused companies.

Last week, major Wall Street indices showed mixed performance. A late-week rally in tech stocks helped the S&P 500 and Nasdaq notch their third weekly gain in four weeks, while the Dow fell 0.7%, snapping a three-week winning streak.

AI stocks rebounded after recent underperformance. Oracle, which had lagged significantly, surged after TikTok agreed to sell its U.S. operations to a new joint venture formed by the software giant and private equity firm Silver Lake. Nvidia also staged a strong comeback.

However, investors are closely watching whether AI stocks can maintain their leadership through year-end, particularly amid concerns about stretched tech valuations and potential rotation into cheaper sectors.

Additionally, doubts linger about the traditional "Santa Claus rally" as the S&P 500 struggles to hold a key technical level.

Justin Bergner, portfolio manager at Gabelli Funds, noted: "A few weeks ago, I expected a challenging consolidation period toward year-end. Now it appears we're seeing heightened volatility instead."