(Adds comments)

NEW YORK, March 6 (Reuters) - Major U.S. stock indexes

declined sharply on Thursday with investors concerned about the

impact President Donald Trump's trade policy may have on

companies and the broader economy, while Marvell Technology's ( MRVL )

revenue forecast sparked concerns about spending on

artificial intelligence infrastructure.

The Nasdaq Composite ended down 10.4% from its

record high close on December 16, confirming the tech-heavy

index has been in a correction since peaking several months ago.

Below are investor comments about the selloff, which

also saw the S&P 500 dip below its 200-day moving average

for the first time since November 1, 2023.

BRIAN NICK, HEAD OF PORTFOLIO STRATEGY, NEWEDGE WEALTH,

ATLANTA

"We're still fairly calm and so are our clients;

selloffs of this magnitude are fairly common, we see about one

every year in the order of magnitude of 10% or more. But what

did catch attention today is that the market was on the verge of

breaking below the psychologically important 200-day moving

average, after which, typically, we'll see another 5% to 8%

correction. Here, our investors are paying attention to the news

flow and how that interacts with the market - and that has been

chaotic. So chaotic, in fact, that I'm surprised we haven't had

a more dramatic spike in volatility. This doesn't feel like an

irrational, completely overdone correction."

JIM CARROLL, PORTFOLIO MANAGER, BALLAST ROCK PRIVATE

WEALTH, CHARLESTON

"If the bounce upward doesn't hold, then people get

nervous and start to take more risk off the table. And the last

two bounces we had, on Friday and on Wednesday, didn't hold, so

clearly we're in risk-off mode again. Clearly people are looking

at what is happening in Washington and wondering how the tariffs

disruption and DOGE upheavals will be beneficial. So the

reaction is to sell some stuff until the market finds a bottom."

ADAM HETTS, GLOBAL HEAD OF MULTI-ASSET, JANUS HENDERSON,

DENVER, COLORADO, AND OLIVE BLACKBOURN, PORTFOLIO MANAGER, JANUS

HENDERSON, LONDON

"What is clear is that markets appear to agree that

tariffs are not good for most risk assets. Given the higher

exposure to global trade and industrial production, it is not

surprising that equity markets outside of the U.S. tend to

suffer when tariff announcements are leading headlines. However,

U.S. equity markets have shown that they are not immune to trade

conflict either. While there are concerns about the potential

inflationary impact of tariffs, U.S. Treasuries have so far

looked to have greater worries about signs of slowing U.S.

growth."

TIM GHRISKEY, SENIOR PORTFOLIO STRATEGIST, INGALLS &

SNYDER, NEW YORK

"The market opened lower, then made a move up, but then

we've had a worse selloff. Trump has been very confusing about

these tariffs. One day they're on and the next day they're off

for a month. He did warn us that there was going to be some pain

initially here, and the market doesn't like pain. I don't think

that's giving investors a lot of confidence. Trump is being

extremely aggressive and that frightens a lot of investors, and

partially because we're just two weeks removed from the all-time

highs, there are at least traders, if not investors, out there

taking profits at these levels. There's no real news here...

It's just some fear here about Trump and his perhaps lack of

concern for the market."

DENNIS DICK, TRADER, TRIPLE D TRADING, ONTARIO, CANADA

"There are a lot of people who are really concerned

about what this trade war is doing, not only directly with the

cost of the tariffs, but with international relations,

altogether. This is a serious concern for the market."

"Maybe I want to reallocate to China, maybe I want to

reallocate to Europe, which has been underperforming for years

and doesn't have this geopolitical risk. ... It just makes sense

that U.S. markets are not the best place to be anymore."

GENE GOLDMAN, CHIEF INVESTMENT OFFICER, CETERA

INVESTMENT MANAGEMENT, EL SEGUNDO, CALIFORNIA

"The Trump bump for equities has now turned into the

Trump slump. Equity markets continue to be in a risk-off

mentality on the combination of market uncertainty and the

overall mixed messages around tariffs emanating from Washington.

In particular, the S&P 500 continues to drive toward the

important key support level at the 200-day moving average

(5730). Any significant breach through that level could send

stocks into correction territory (around 5500 for the S&P 500)."

MARK HACKETT, CHIEF MARKET STRATEGIST, NATIONWIDE,

DOWNINGTOWN, PENNSYLVANIA

"I think the rapidity with which the decline has

happened is a little bit overdone. I would say half of the

(recent selloff) was really attributable to fears of growth data

coming in weak. Since then the back and forth .. . the tariff

discussion on again, off again, is making people have a little

bit of a temper tantrum."

"I think people are hitting the panic button because

number one, there is this temper tantrum from lack of clarity on

tariffs and then you line that up with the growth concerns."

"I think that this is an emotional driven selloff that

is more likely to become a buying opportunity than a selling

opportunity. There's not enough data out there to justify the

move that we've seen."

ART HOGAN, B. RILEY, MARKET STRATEGIST, BOSTON

"The administration seems to be trying to play a ping pong

game by announcing something and then pulling it back on

tariffs, but this time it's not working. People reacted to

Howard Lutnick's attempt to calm the markets with distrust.

Clearly, there are signs of a slowdown ahead of any tariffs

really digging in and faced with uncertainty, consumers,

corporate leaders and investors are all going to freeze and put

off longer-term business plans."

"At this point, there's nothing left to give the market a

boost now that the excitement of electing a president who was

seen as pro-business has worn off."

SAM STOVALL, MARKET STRATEGIST, CFRA, ALLENTOWN,

PENNSYLVANIA

"The longer that these tariffs remain in place, the lower

that the market is likely to go because of the increasing threat

of inflation and recession."

"To make markets feel good, it would have to be a more broad

based and more sweeping lift of the tariffs, not just individual

sectors, such as automakers."

"Marvell ( MRVL ) earnings is also causing investors to

think the AI-trade is slowing down, and it's time to take

profits now that we can. The combination of tariffs and

technology has been explosive for stock prices."

BILL STERLING, GLOBAL STRATEGIST, GW&K INVESTMENT

MANAGEMENT, BOSTON

"A continuation of this on-again, off-again with tariffs

particularly with Mexico and Canada (is what is creating

uncertainty in markets)."

"The rational economic response to business leaders when

there's such a high degree of uncertainty is to sit on their

hands and just defer making decisions."

"The other is simply the size of the tariffs. This is way

beyond what was experienced in 2018 with the you know so-called

China trade war and this could raise inflation, which is what

the Fed cares most about, by a full percentage point or a little

bit more over the next year."

BRIAN JACOBSEN, CHIEF ECONOMIST, ANNEX WEALTH MANAGEMENT,

MENOMONEE FALLS, WISCONSIN

"On-again, off-again tariffs may be worse than just getting

the tariffs done with. The uncertainty isn't resolved, it's just

prolonged. Businesses will still try to hike prices just in

case. Consumers may be more willing to accept price increases

because they're afraid of how much higher prices could go. It's

not a healthy dynamic. The Fed isn't in a position to run to the

rescue."

CAROL SCHLEIF, CHIEF MARKET STRATEGIST, BMO PRIVATE WEALTH,

MINNEAPOLIS, MINNESOTA

"A combo of things has come spilling out the worry closet

this week - tariffs started it (their actual imposition) and it

continues given the flip flopping. Businesses are having a tough

time adjusting and the data out recently - including this week -

show. Sentiment (business and consumer) is down, inventories way

up, job losses are mounting, and commentary from the Fed's beige

book all indicate business is having a tough time planning and

consumers are concerned."

"Recent tech earnings reports are still making investors

question how much longer the data center build-out goes on, even

as excitement grows in use cases by more (and smaller)

businesses."