Japanese shares slid on Wednesday to their biggest one-day percentage drop this year, as caution prevailed across Asia after a surprise cut on the U.S. credit rating weighed on sentiment.

Then benchmark 225-issue Nikkei average closed down 2.30% at 32,707.69 in its sharpest one-day drop since Dec. 20, while the broader Topix slipped 1.54% to 2,301.26.

"Japan's chip-related stocks tracked declines in the Nasdaq, which weighed on Japanese shares," said Masahiro Ichikawa, chief market strategist at Sumitomo Mitsui DS Asset Management.

"And investors were cautious after Fitch ... cut the U.S. credit rating."

Ratings agency Fitch on Tuesday downgraded the United States to AA+ from AAA in a move that drew an angry response from the White House and surprised investors, coming despite the resolution two months ago of the debt ceiling crisis.

"The possibility of a downgrade was raised during the recent crisis, and showed Fitch as concerned about the whole political process of debt ceiling increases as they were about the binary question of the increase itself," ING economists said in a note.

MSCI's broadest index of Asia-Pacific shares outside Japan shed 2%, on course for its worst day since February.

In Japan, semiconductor equipment maker Tokyo Electron slipped 3.12% and chip-testing equipment maker Advantest lost 4.48%.

Shares of Nomura Holdings tanked 8%, its biggest one-day drop since March 2021, even as the nation's top brokerage reported a jump in first-quarter net profit.

Its losses sent the brokerage sector down nearly 5% to make it one of the worst performers among the 33 industry sub-indexes on the Tokyo Stock Exchange.

Meanwhile, Toyota rose 2% after the automaker nearly doubled its operating profit in the first quarter.