Japan's Nikkei share average surrendered early gains to end lower on Tuesday, as investors slowed activity ahead of U.S. chipmaker Nvidia's earnings report.

The Nikkei fell 0.31% to 38,946.93, after rising as much as 0.7% earlier in the session.

The index rose 0.78% in the previous session, hitting 39,000 level for the first time in a month.

The broader Topix fell 0.3% to 2,759.72.

"The Nikkei's momentum didn't last as investors refrained from active buying before Nvidia's earnings on Wednesday," said Shigetoshi Kamada, general manager at the research department at Tachibana Securities.

Air-conditioner maker Daikin Industries fell 4.68% to become the biggest drag on the Nikkei. Technology investor SoftBank Group lost 1.64%.

Chip-related shares rose, with Advantest and Tokyo Electron rising 1.45% and 0.8%, respectively.

Insurers were strong, with MS&AD Insurance Group surging 13.79% after the company said on Monday its group net profit is forecast to rise 65% and that it would buy back up to 8.2% of its shares.

Peer Tokio Marine Holdings rose 2.34% after announcing it would sell down cross-share holdings to zero by the end of fiscal 2029/30.

The insurance sector rose 2.29% to become the best performer among the Tokyo Stock Exchange's (TSE) 33 industry sub-indexes.

Sompo Holdings fell 6% as the insurer flagged a 45% decline in its annual net profit.

KFC Holdings rose to a daily limit high of 6,400 yen, after being untraded with a glut of buy orders, as the operator of Kentucky Fried Chicken outlets said U.S. buyout fund Carlyle Group offered to buy shares of the company at 6,500 yen per stock.

Of more than 1,600 stocks trading on the TSE's prime section, 34% of shares rose and 61% fell with 4% being flat.

(Reporting by Junko Fujita; Editing by Mrigank Dhaniwala)