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South Korea leads declines, plunging as much as 6.2%

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Nikkei down almost 7% from Tuesday's record high

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Bitcoin, gold attempt recovery after selloff

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Wall Street CEOs question sustainability of rally

(Updates market levels, adds China markets and PMI data)

By Gregor Stuart Hunter

SINGAPORE, Nov 5 (Reuters) - Asian stocks dived on

Wednesday and market volatility surged to levels not seen since

April after an overnight tech-led selloff on Wall Street put the

spotlight on stretched valuations.

Sellers were particularly harsh on both the Japanese and

South Korean markets in early trading with Tokyo's stock index

tumbling 4.5%, down almost 7% from a record high reached

on Tuesday. South Korean shares plunged as much as 6.2%.

MSCI's broadest index of Asia-Pacific shares outside Japan

was down 2.3%, the most since U.S. President

Donald Trump's Liberation Day tariff announcement in early

April. U.S. e-mini futures slumped 0.6% after a 1.2% drop

for the S&P 500 overnight.

In Japan, shares in SoftBank Group dived 10% as one

of the world's biggest tech sector investors tracked a 2% drop

in the Nasdaq Composite overnight.

"It's a sea of red across broad markets," said Chris Weston,

head of research at Pepperstone Group in Melbourne. "There

aren't many reasons to buy here, and until we move closer to

Nvidia's earnings on 19 November, the market lacks a short-term

catalyst."

Stocks are retreating from record highs on fears equity

markets may have become overstretched after the CEOs of Wall

Street heavyweights Morgan Stanley ( MS ) and Goldman Sachs ( GS )

questioned whether sky-high valuations can be sustained.

Last month, banking giant JPMorgan Chase's ( JPM ) CEO Jamie

Dimon had warned of a heightened risk of a significant

correction in the U.S. stock market within the next six months

to two years.

The warnings come as a surge in enthusiasm for generative AI

has swept across stock markets worldwide this year, drawing

comparisons to the dot-com bubble.

"At some point, profits need to be booked. Especially when

we've seen repeatedly solid runs to record highs," said Matt

Simpson, senior market analyst at StoneX in Brisbane. "Those

with money on the line aren't likely seeking answers right now -

they're just copying each other like kids in an exam. And the

answer is to run."

Chinese shares dropped, with the CSI 300 falling

0.6% after a private sector gauge of service sector PMI activity

expanded at its slowest pace in three months.

The U.S. dollar dropped 0.3% against the yen to 153.16

after the release of minutes from the Bank of Japan's

September policy meeting.

The dollar index, which tracks the greenback against

a basket of currencies of other major trading partners, edged

back after touching a five-month high of 100.25.

The yield on benchmark 10-year Treasury notes

edged lower to 4.058% compared with its U.S. close of 4.091% on

Tuesday.

Bitcoin fell below $100,000 for the first time since

June and was choppy afterwards, with the cryptocurrency last up

1% at $101,233.90. Gold rebounded after three consecutive

days of losses, and was trading 0.2% higher at $3,938.54 per

ounce.

The European single currency held steady at $1.1487

after hitting a three-month low following five straight days of

declines.

Brent crude was last 0.6% lower at $64.05 per

barrel.