(For a Reuters live blog on U.S., UK and European stock

markets, click or type LIVE/ in a news window.)

*

Futures down: Dow 0.7%, S&P 500 1%, Nasdaq 1.3%

Nov 4 (Reuters) - U.S. stock futures tumbled on Tuesday

as investors questioned lofty valuations in the technology

sector after top Wall Street banks warned of a stock market

selloff and AI darling Palantir's ( PLTR ) sales forecast failed to lift

the mood.

The chief executives of Goldman Sachs ( GS ) and Morgan

Stanley ( MS ) warned in an investment summit in Hong Kong of a

stock market correction of more than 10% over the next two

years.

Palantir Technologies' ( PLTR ) shares slid 6.6% in

premarket trading even as the data analytics company forecast

fourth-quarter revenue above analysts' estimates. The stock has

jumped nearly 400% in the past year.

Wall Street indexes touched all-time highs last week and

marked solid gains for October as quarterly reports from several

Big Tech companies signaled surging investments on artificial

intelligence, a key driver of the bull run in U.S. equities this

year.

However, doubts surrounding the circular nature of the

spending and monetization of the technology have resurfaced,

spurring investors to pull back after a breakneck rally in

AI-related stocks.

"It just feels like there's been so much talk that the

market is overbought and there's a lot of overvalued stuff there

that's concentrated in tech," said David Morrison, senior market

analyst at Trade Nation.

The rally will be under renewed scrutiny with semiconductor

company Advanced Micro Devices ( AMD ) reporting after the bell

on Tuesday and Qualcomm ( QCOM ) later in the week.

Big names reporting before the bell include Uber ( UBER ),

Pfizer ( PFE ), Marriott International ( MAR ), Yum Brands ( YUM )

and Shopify.

At 06:01 a.m., Dow E-minis fell 337 points, or

0.71%, S&P 500 E-minis shed 68.25 points, or 0.99%, and

Nasdaq 100 E-minis lost 336.25 points, or 1.29%.

The CBOE Volatility Index, Wall Street's fear gauge,

was near a two-week high.

DATA DARKNESS DIMMING DECEMBER HOPES

With the U.S. government shutdown likely to become the

longest ever, Fed officials have been left in the dark without

data to rely on. Wednesday's ADP National Employment data will

take on renewed importance as a gauge of the labor market.

Recent conflicting commentary from Fed officials has

indicated differing perspectives on how to handle the data gap.

Chicago Fed President Austan Goolsbee said he was on the

fence about cutting rates in December, with inflation still far

above the central bank's target, while Governor Stephen Miran

called the current monetary policy too restrictive.

Traders are now pricing in a 70% chance of a 25-basis-point

rate cut in December, lower than 90% a week earlier, according

to CME Group's FedWatch tool.

Sarepta Therapeutics ( SRPT ) shares dropped 40% in premarket

trading after a trial for its muscle-wasting disease drug missed

a key goal.

Hims and Hers topped revenue estimates for the

third-quarter, sending shares rising 0.7%.