TOKYO, June 1 (Reuters) - Japan's Nikkei share average

topped 67,000 for the first time on Monday, powered by

AI-related shares, as startup investor SoftBank Group overtook

Toyota Motor ( TM ) to become the country's most valuable company.

The Nikkei climbed 1.1% to enter the midday recess

at 67,038.24, after pushing as high as 67,231.28.

SoftBank was by far the biggest support for the

index, jumping 10.3% to contribute 618 points of the Nikkei's

total 709-point rise.

The company's market capitalisation swelled to around 47.2

trillion yen ($296.0 billion), while Toyota's ( TM ) shrank to

around 45.7 trillion yen after the stock slid 4.8% on Monday.

Over the weekend, SoftBank pledged some 75 billion euros

($87.3 billion) over five years to build up AI infrastructure in

France.

The split between tech shares and the rest of the market was

clear from the performance of the broader Topix, which

sagged 0.2%.

Both the Nikkei and Topix had notched all-time highs on

Friday on optimism over a near-term peace deal in the Middle

East, but the fresh week began with Washington and Tehran still

appearing to differ on significant issues.

"Given the current expectations for expanding demand for AI

servers, buying interest is spreading to AI-related stocks that

had been lagging behind," such as electronic component maker

Murata Manufacturing ( MRAAF ), said Maki Sawada, a strategist at

Nomura Securities.

Shares of Murata surged 14.1% to be the Nikkei's biggest

percentage risers.

At the same time, "we're in a situation where concerns about

overvaluation are deep-rooted," particularly with uncertainty

around the Middle East still high, she said.

Among the Tokyo Stock Exchange's 33 industry groups, eight

rose, led by a 4.3% jump in IT firms. Auto shares

were among the worst performers, down 4.2%.

Even in the Nikkei, only 73 of its 225 components rose,

versus 152 that fell.

Not all chip-related shares advanced, with Advantest ( ADTTF )

retreating 2.2% and Fujikura ( FKURF ) down 3.6%.

Mitsubishi Motors ( MMTOF ) was the biggest percentage

decliner, tumbling 9.1%. Alliance partner Nissan ( NSANF ) was

another standout loser, declining 7.2%.

($1 = 159.4700 yen)

($1 = 0.8588 euros)