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

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

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Indexes up: Dow 0.06%, S&P 500 0.24%, Nasdaq 0.55%

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Nvidia ( NVDA ) first company to hit $4 trillion market value

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AES ( AES ) jumps on report of sale efforts

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UnitedHealth ( UNH ) down on report of DOJ's Medicare billing

probe

(Updates with early afternoon prices)

By Pranav Kashyap and Nikhil Sharma

July 9 (Reuters) -

Wall Street's main indexes ticked up on Wednesday as Nvidia ( NVDA )

rocketed to a $4 trillion valuation, while investors took in

their stride President Donald Trump's latest tariff salvo.

Nvidia ( NVDA ) rose 2% and became the first company in the

world to hit a $4 trillion market value, solidifying its

position as one of Wall Street's most favored stocks to tap in

the ongoing surge in demand for AI technologies.

"It highlights the fact that Nvidia ( NVDA ) is sort of the

backbone of artificial intelligence infrastructure and it is

indicative of the revolution that's going on in technology. I

believe that there's still more upside in the stock," said

Robert Pavlik, senior portfolio manager at Dakota Wealth.

At 11:25 a.m. ET, the Dow Jones Industrial Average

rose 28.16 points, or 0.06%, to 44,268.92, the S&P 500

gained 15.29 points, or 0.24%, to 6,240.73 and the Nasdaq

Composite was up 111.90 points, or 0.55%, to 20,530.36.

Six of 11 S&P sectors clocked gains, with the technology

index rising 0.44% and communication services

leading by 1.3%.

Trump ramped up his trade offensive on Tuesday,

announcing a 50% tariff on copper and vowing to slap

long-threatened levies on semiconductors and pharmaceuticals.

This came just a day after he jolted 14 trading partners

with a fresh wave of tariff warnings, and said that at least

seven new notices would drop later in the day.

Markets' reaction have been relatively stable with

analysts noting that investors have become used to Trump's

pattern of saber-rattling on tariffs, and that the White House

will potentially back down from its most aggressive threats.

With the deadline for new tariffs pushed to August 1,

investors are betting that negotiations will defuse the risk of

a full-blown trade war.

"The tariff issue continues to be this sort of seesaw and

because of that back-and-forth, it obviously has given investors

a bit of a calm," said Philip Blancato, chief market strategist

at Osaic Wealth.

The European Union said it could reach an outline trade

agreement with the U.S. in the coming days.

Meanwhile, after last week's record closes for the S&P 500

and the Nasdaq - buoyed by a surprisingly robust jobs report

-investors are turning their attention to Thursday's initial

jobless claims for the next pulse check on the labor market.

Traders will also parse through the minutes from the Federal

Reserve's June meeting, due at 2:00 p.m. ET, for any hints about

when policymakers might resume easing rates.

While a July rate reduction is almost fully ruled out, the

odds of a September cut stand at about 64%, according to CME

Group's FedWatch tool.

Trump's erratic tariff actions have sparked concerns about

global growth and inflation, while also complicating the work of

the Fed, which has adopted a wait-and-see approach on monetary

policy.

Among stocks, AES Corp ( AES ) jumped 16.6% after Bloomberg

reported that the power provider was exploring options,

including a sale.

Health insurer UnitedHealth Group ( UNH ) slipped 2.4% after

the Wall Street Journal reported that the U.S. Department of

Justice was investigating how the company deployed doctors and

nurses to gather diagnoses that increased its Medicare payments.

Boeing ( BA ) advanced 4.1% as Susquehanna raised its price

target after the planemaker on Tuesday reported that its

airplane deliveries in June increased by 27% on a yearly basis.

Advancing issues outnumbered decliners by a 1.07-to-1 ratio

on the NYSE and by a 1.05-to-1 ratio on the Nasdaq.

The S&P 500 posted 13 new 52-week highs and five new

lows, while the Nasdaq Composite recorded 48 new highs and 34

new lows.