(Updates with closing prices.)

By Rocky Swift

TOKYO, Nov 19 (Reuters) - Japan's Nikkei share gauge

lost ground for a fourth day on Wednesday as investors remained

wary ahead of pivotal earnings from artificial intelligence

heavyweight Nvidia ( NVDA ).

The Nikkei 225 Index swung between gains and losses

before closing down 0.3% to 48,537.70, marking its longest

losing streak in seven weeks. The broader Topix dipped

0.2%.

Japan's blue-chip share gauge sank by the most in more than

seven months in the previous session as concerns about the

valuations of technology-related companies rattled global equity

markets. U.S. stocks ended lower overnight, with Nvidia's ( NVDA ) shares

sliding 2.8%. The company will report quarterly results after

the close in New York on Wednesday.

A sharp rise in Japanese government bond yields, spurred by

concerns about stimulus spending along with diplomatic tensions

with China, also acted as drags on the nation's shares, said

Nomura Securities strategist Fumika Shimizu.

"The decline in semiconductor-related stocks and rising

interest rates seem to be weighing on the market," Shimizu said.

"The focus will be on whether (Nvidia ( NVDA )) can show revenue or

profit forecasts that exceed market expectations."

There were 112 advancers on the Nikkei index against 111

decliners. The largest gainers in the index were retailer Aeon

, up 4.6%, followed by cinema operator Toho (Tokyo)

, which climbed 3.9%.

The biggest losers were Sumco ( SUMCF ), down 6.26%, followed

by Ibiden ( IBIDF ), which slid 4.1%.