Japan's Nikkei rises as tech shares gain on AI investment plans

TOKYO, Jan 22 (Reuters) - Japan's Nikkei share average rose on Wednesday, as investors scooped up SoftBank Group and other technology stocks after U.S. President Donald Trump announced a private sector investment of up to $500 billion to fund AI infrastructure.

The Nikkei .N225 had risen 1.48% to 39,604.71 by the midday break. Earlier in the day, it hit its highest level since Jan. 9 at 39,647.83.

Trump said that ChatGPT's creator OpenAI, SoftBank Group 9984.T and Oracle ORCL.N are planning a joint venture called Stargate, which he said will build data centres and create more than 100,000 jobs in the United States.

"Today's market is dominated by the news about Trump's AI investment announcement. Investors have already shrugged off concerns about his tariff plans and instead focused on positive elements," said Shuutarou Yasuda, a market analyst at Tokai Tokyo Intelligence Laboratory.

SoftBank Group 9984.T jumped 9%, providing the biggest boost to the Nikkei. Chip-testing equipment maker Advantest 6857.T, a supplier to Nvidia NVDA.O, rose 3.94% and chip-making equipment maker Tokyo Electron 8035.T gained 2.31%.

Makers of materials for data centres also rose, with Furukawa Electric 5801.T and Fujikura5803.T surging 12% each to become the top gainers on the Nikkei.

The broader Topix .TOPX rose 0.94% to 2,738.91, posting a smaller gain than the Nikkei as financial stocks fell.

Insurer Tokio Marine Holdings 8766.T fell 1.2% and Dai-ichi Life Holdings 8750.T lost 0.96%.

Banks fell, with Mizuho Financial Group 8411.T and Sumitomo Mitsui Financial Group 8316.T slipping 0.23% and 0.32%, respectively.

Topix's growth index .TOPXG rose 1.22%, while the value share index .TOPXV gained 0.67%.

Of the more than 1,600 shares trading on the Tokyo Stock Exchange's prime market, 65% rose and 30% fell, with 3% flat.

(Reporting by Junko Fujita; Editing by Subhranshu Sahu)

((junko.fujita@thomsonreuters.com;))