*

Indexes down: Dow 0.54%, S&P 500 0.96%, Nasdaq 1.58%

*

Palantir ( PLTR ) slides despite estimate-topping Q4 revenue

forecast

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Uber ( UBER ) slides as Q4 adjusted core profit misses estimates

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Advanced Micro Devices ( AMD ), Super Micro Computer ( SMCI ) results due

after

the bell

(Updates to afternoon)

By Stephen Culp

NEW YORK, Nov 4 (Reuters) - U.S. stocks veered sharply

lower on Tuesday as big banks warned that equity markets could

be headed for a drawdown, reflecting mounting concerns over

stretched valuations.

All three major U.S. stock indexes slid well into negative

territory after the CEOs of Morgan Stanley ( MS ) and Goldman

Sachs ( GS ) stoked fears of a potential market bubble, with the

S&P 500 having climbed to a series of all-time highs, largely

powered by the artificial intelligence boom.

Tech shares weighed particularly heavily on the

Nasdaq, with six of the "Magnificent Seven" AI-related momentum

stocks losing ground on the day.

Results from Advanced Micro Devices ( AMD ) and Super Micro

Computer ( SMCI ), expected after the bell on Tuesday, could

offer insight regarding the momentum and staying power of the

AI-driven bull run.

The Philadelphia SE Semiconductor index dipped 2.8%.

JPMorgan Chase ( JPM ) CEO Jamie Dimon warned last month of the

heightened risk of a significant stock market correction within

the next six months to two years, citing factors including

geopolitical tensions.

"To say in the next 12 to 24 months that we might have a 10%

to 20% correction is like, so what?" said Thomas Martin, senior

portfolio manager at GLOBALT in Atlanta. "Markets have

corrections all the time."

"It's a good thing for the market to have corrections, and

it doesn't mean that it won't recover," Martin added. "It's not

like it's going to go down 10% and stay down. You've got to have

down days."

The U.S. government shutdown, the result of a congressional

impasse, is nearing the record for the longest ever. The

resulting dearth of official government data has led to

increased scrutiny of private sources such as ADP's National

Employment index expected Wednesday.

Comments from Federal Reserve officials are being parsed for

clues as to how the data-dependent central bank will forge its

monetary policy in the absence of crucial economic indicators.

Local elections for New York's mayor and governors in New

Jersey and Virginia will also be closely tracked.

The Dow Jones Industrial Average fell 257.15 points, or

0.54%, to 47,079.53, the S&P 500 lost 66.08 points, or

0.96%, to 6,785.89 and the Nasdaq Composite

dropped 376.37 points, or 1.58%, to 23,458.35.

Tech was down the most among the 11 major sectors comprising the

S&P 500, falling 1.9%. Consumer staples led the

gainers.

Palantir Technologies ( PLTR ) slid 7.9% despite the data

analytics company's better-than-expected fourth-quarter revenue

forecast. The stock has soared over 152% in the past year.

Uber ( UBER ) fell 5.7% in the wake of the ride-hailing

platform's quarterly profit miss, while Henry Schein

advanced 9.1% after hiking its annual profit forecast.

Spotify ( SPOT ) and U.S.-listed shares of Shopify ( SHOP )

dipped 3.3% and 5.1%, respectively, after their quarterly

results.

Declining issues outnumbered advancers by a 2.63-to-1 ratio

on the NYSE. There were 54 new highs and 154 new lows on the

NYSE.

On the Nasdaq, 1,093 stocks rose and 3,522 fell as declining

issues outnumbered advancers by a 3.22-to-1 ratio.

The S&P 500 posted 11 new 52-week highs and 18 new lows

while the Nasdaq Composite recorded 42 new highs and 229 new

lows.