(Reuters) - The S&P 500 closed below 5,000 points for the first time in almost a year, reversing a strong morning rally as hopes faded for any imminent U.S. delays or concessions on tariffs ahead of a midnight deadline.

The benchmark index fell 1.6% on Tuesday marking a $5.8 trillion loss in market value since President Donald Trump unveiled hefty global tariffs against U.S. trading partners on Wednesday. This represented more than 12% for its biggest four-day percentage decline since the pandemic.

By finishing almost 19% below its record close on Feb. 19, it also was on the cusp of a 20% selloff that would denote a bear market. The Dow Jones Industrial Average fell 0.84%, while the Nasdaq Composite 2.15%.

COMMENTS:

MARK MALEK, CHIEF INVESTMENT OFFICER, SIEBERT FINANCIAL, NEW YORK

"It's not good, this kind of market close. Even though the rally lost steam in the afternoon, we could have, should have had a better close. Stocks have already factored in a trade war and there wasn't enough new news to knock the market down further by changing what is already priced in materially.  There are going to be a lot of technical traders tonight scratching their heads."But I'm still slightly positive, which is rare for me recently. I think the body language coming from the administration signals that they'd rather negotiate, that the 104% tariffs on China we heard about later in the session are a negotiating tactic."

PETER TUZ, PRESIDENT, CHASE INVESTMENT COUNSEL CORP, CHARLOTTESVILLE, VIRGINIA

    "Early in the day, the market kind of had some indication that there might be a quicker fix to the tariff issue than we thought last week. But as the day wore on and the news came out, that thought went away and uncertainty about everything -- earnings, tariffs -- going forward just grew again and the market sold off."

    "I don't even know how you begin to make an (earnings) estimate for a lot of companies right now. ... So I just view any earnings estimate made right now for a lot of companies and for the S&P 500 as fraught with huge potential for change, probably to the downside. And it's just hard to put a value on the market in many stocks until you have some comfort in the earnings going forward."

CHRIS GRISANTI, CHIEF MARKET STRATEGIST, MAI CAPITAL MANAGEMENT, NEW YORK

"I found the market reaction today troubling. Of course, we were elated to see the strong market this morning, and then making this finish that much worse, because it took our joy and turned it into sorrow.

"But on a more technical level, it makes a lot of sense to me, because how can you really make meaningful investments at this stage when there's so much uncertainty? I think you need a level of humility here to be able to admit that there's a lot of stuff we just don't know. I strongly think, at this point, 'caution' is the better watch word, rather than 'looking for opportunities'.

"I think it will be difficult for the economy to avoid a recession, even if the tariffs disappeared tomorrow. Because I think things are very seized up, meaning things are not moving because the businesses, especially, don't know what decisions to make. So, they're just not making any decision. So, I think we're just about beyond the point of no return. We're going to start seeing first quarter numbers starting on Friday, I wouldn't be at all surprised to see companies pulling guidance left and right that they gave in January. There's a lot of bad stuff that still has the potential to happen over the next couple of weeks."

(Compiled by the Global Finance & Markets Breaking News team)