TOKYO, Jan. 23 (Xinhua) -- Japan's key stock index extended its gains for a fourth consecutive day on Thursday, bolstered by gains in U.S. stocks driven by optimism over artificial intelligence (AI) investments.
The benchmark Nikkei stock index, the 225-issue Nikkei Stock Average, closed 312.62 points, or 0.79 percent higher, at 39,958.87.
The Nikkei briefly surpassed the 40,000 mark for the first time since Jan. 8, tracking U.S. stock market gains that were fueled by expectations of increased AI development investments.
While profit-taking near the psychological threshold of 40,000 temporarily capped gains during the morning session, consistent buying in index futures helped the Nikkei maintain its momentum in the afternoon.
The broader TOPIX index also rose for the fourth straight session, gaining 14.55 points, or 0.53 percent, to end at 2,751.74.
On the Tokyo Stock Exchange Prime Market, advancing issues numbered 639, while 936 declined, and 68 were unchanged. ■
