SINGAPORE (Reuters) -Asian markets struggled to make headway on Wednesday as a bout of nerves over AI valuations held back investors ahead of an earnings update from chip titan Nvidia ( NVDA ).

The tech-heavy Nasdaq fell 1.2% overnight, notching a second straight day of losses. Valuation jitters have knocked it more than 6% below a record peak hit late in October. [.N]

S&P 500 futures and Nasdaq 100 futures teetered around flat in the Asia morning. Japan's Nikkei made an unsteady 0.4% gain and South Korea's Kospi fell 0.8%.

Nvidia ( NVDA ), which sells the graphics processing units (GPUs) underpinning artificial intelligence, has been at the heart of a rally that has carried stock markets around the world to record highs and lifted any stock with even tangential links to AI.

It reports after market close in the U.S. and is expected to deliver a 56% jump in its fiscal August-October quarter revenue to $54.92 billion, according to data compiled by LSEG.

"It looks like Nvidia's ( NVDA ) stock price has been priced for perfection, so GPU demand must continue to grow strongly for many more years for the stock to stay up," said Wong Kok Hoi, founder and CEO of APS Asset Management in Singapore.

JAPAN BONDS SLIDE

Simultaneously doubts are growing that the U.S. will cut interest rates again in December and investors worry that U.S. President Donald Trump's falling approval rating could drive fiscal spending and possibly stoke inflation.

That has held back safe-haven U.S. Treasuries from gains even as the market mood has soured. Yields did fall overnight, but only slightly, and the benchmark 10-year yield was last steady at 4.11%. [US/]

Markets are pricing about a 42% chance of a 25-basis point Federal Reserve rate cut in December, something that was priced as a near certainty a month ago.

"If, and it's an if, growth does turn down, will there be able to be as much fiscal support as there was during the pandemic or during the global financial crisis given governments' fiscal positions are significantly worse now?" said Nomura chief economist Rob Subbaraman.

In Japan, concern over ballooning government spending plans has sent long-end bonds sliding and yields to record highs.

A 20-year auction later on Wednesday will be closely watched and benchmark 10-year yields hit a 17-year top of 1.765%. [JP/]

BITCOIN BOUNCES BACK FROM BELOW $90,000

Mood-barometer bitcoin has recovered slightly from a trip to a seven-month low on Tuesday to trade at $92,000. That's still down 27% from October's record high.

"BTC has erased this year's gains and then some, meaning anybody who acquired in the past 10 months is underwater," said Justin d'Anethan, head of research at Arctic Digital, a crypto investment and advisory firm.

"But I don't think this is the beginning of a bear market, just a reaction to equities falling, disappointing rate cut expectations and leverage getting cleared out."

Foreign exchange markets were broadly on hold, with buyers drifting to dollars. The yen was squeezed at 155.45 per dollar and heading into territory where authorities have warned of intervention. [FRX/]

The euro was kept to $1.1582, and the Australian and New Zealand dollars were a little lower in morning trade.

Gold, which scaled record highs alongside stocks in October, has also fallen and nursed losses at $4,066 on Wednesday. [GOL/]

Brent crude futures edged 35 cents lower to $64.51 a barrel. Soybeans have touched a 17-month high after China made hefty purchases of U.S. supplies. [O/R][GRA/]