U.S. stock markets on Thursday spent most of the day deep in the red in an across-the-board rout triggered by the prospect that a U.S.-China trade deal was in jeopardy.

Investor angst was fueled by the arrest of a Chinese executive that further threatened progress on trade, coupled with omens of a recession in the bond market and a steep drop in oil prices.

At its low, the Dow Jones industrial average fell 784 points, or 3.1 percent. By the final hour of trading, it had clawed its way back and closed the day down 78 points, or 0.3 percent.

In a tremendous late-day rally, the tech-heavy Nasdaq pulled into positive territory, ending up 0.4 percent. And the Standard & Poor's 500-stock index came back to finish down just 0.15 percent.

Investors seemed heartened by comments from JPMorgan Chase CEO Jamie Dimon and Christine Lagarde, managing director of the IMF.

"On the actual effects on the ground, you still have a strong economy," Dimon said in an interview with CNBC. He stressed repeatedly that the economic fundamentals still look good.

Lagard said global slowdown fears are overblown. "It's a little bit overdone - 3.7 percent forecasts for [global] growth is not bad," Lagarde said, also on CNBC.

Markets also were buoyed by news reports that the Federal Reserve may delay an anticipated December interest rate increase.

Oil prices remained down, however. The Organization of Petroleum Exporting Countries began a crucial meeting Thursday in Vienna in hopes of agreeing on a production cut of 1 million barrels per day.

Oil prices are down 30 percent in the fourth quarter on overproduction across world producers.

Prices slipped further Thursday on fears that Saudi Arabia will not cut production enough to stabilize prices. Anything short of 1 million barrels per day would likely be disappointing for producers.

The big three oil producers are now the United States, Russia and Saudi Arabia. Saudi Arabia and non-OPEC Russia are key to reducing production.

President Donald Trump took to Twitter to weigh in: "Hopefully OPEC will be keeping oil flows as is, not restricted. The World does not want to see, or need, higher oil prices!"

International benchmark Brent crude dropped 2.1 percent overnight to $60.28 a barrel. U.S. West Texas Intermediate crude slid 2.3 percent to $51.66. Experts consider $50 as a key threshold because many producers cannot turn a profit if prices plunge much below that number.

The OPEC meeting Thursday apparently ended with no agreement and debate expected to continue Friday, when Russia is supposed to attend.

"OPEC needed to send a strong signal to the market today, and the group failed to do so," said oil analyst John Kilduff of Again Capital Management. "The fact there is an ongoing debate, with no sense of the contours of an accord, is a large negative for prices. There appears to be more disunity than unity."

Kilduff said Iran and Iraq are refusing to cut, and Libya has insisted on continuing to be exempted from the quota regime, which was granted.

"At this point, any reduction short of 1.3 million barrels per day, which would include Russian participation, will result in a sell-off beyond what we are already seeing."

Kilduff said if Friday's meeting fails, the WTI oil price could fall as low as $40 per barrel.

Mixed signals about the status of the trade deal between the U.S. and China following the Group of 20 Summit in Buenos Aires unleashed to a calamitous Tuesday on Wall Street, with the Dow plunging 800 points, or 3 percent. President Trump and the Chinese Commerce ministry touted their successful negotiations, but Trump's claims about tariff reductions and Beijing buying more U.S. agriculture and natural gas weren't backed up by his own administration or the Chinese government.

"Trump administration claim that there would be short-term pain associated with the tariffs to correct the wrongs now looks like it might be more of a long-term drag on investor and business confidence," Chris Rupkey, chief financial economist of MUFG Union Bank wrote in a note to investors Thursday morning. "The odds of recession the next two years have risen dramatically, and if one does occur, it will be the Trump recession."

U.S. financial markets were closed Wednesday for the state funeral of President George H.W. Bush.

By Thursday, news had emerged that chief financial officer of Chinese tech juggernaut Huawei, Meng Wanzhou was arrested in Canada and now faces extradition to the United States. While the Canadian government declined to share the details of her arrest, the Wall Street Journal reported in April that Meng was under investigation for possible violations of U.S. sanctions against Iran. Meng's arrest bodes poorly for the already fragile detente between the U.S. and China ahead of another 90 days of trade negotiations.

The news sowed further fears in Asian markets Thursday. Hong Kong's Hang Seng index sank 2.7 percent and The Shanghai Composite index fell 1.7 percent and Japan's benchmark Nikkei tumbled 2.3 percent.

The jitters spread to European markets, with Britain's FTSE 100 Index falling more than 2.5 percent and Germany's DAX index faring even worse, down more than 2.8 percent. In France, the CAC fell nearly 2.8 percent.

Investors were also spooked by something that hasn't happened in a decade: the inversion of the yield curve. Typically, the interest rate on 5- and 10-year U.S. government bonds are higher than the interest rates paid for bonds of 3 years or less. Investors who are loaning the U.S. government money for a long time tend to want a higher interest rate for taking on that extra risk. But on Monday the 3-year bond was yielding more than the 5-year bond, an unusual event that Wall Street is viewing with concern.

Inverted yield curves usually mean a recession is coming, although not immediately.

"Although an inverted yield curve is a good indicator of trouble, it has never been a good sign of immediate trouble," said Brad McMillan, chief investment officer at Commonwealth Financial Network. "There has typically been a delay of two years or more between the initial inversion and the actual recession."

Investors are closely watching for when the 3-month yield climbs above the 10-year bond yield. That hasn't happened yet, but is typically a more clear indicator of a coming recession than what has occurred so far. Still, investors are reading this week's events as more confirmation that the U.S. economy has likely peaked and is going to slow down from here.

Also on the horizon: Friday's jobs report.

"Markets are being flailed by a flurry of worrisome inferences that include the 2-year-to-5-year yield-curve inversion, skepticism toward a near-term resolution to the ongoing trade dispute and the possibility that Friday's employment report will be strong enough to delay the Fed's anticipated slowdown in its pace of rate increases," said Sam Stovall, investment strategist at CFRA Research.

If stocks don't rebound and interest rates keep rising, it makes it more expensive for businesses to borrow money and invest for the future. That, in turn, slows growth. While the overall economy looks healthy right now, sentiment could shift quickly if markets stay down.

“Trump blames others and says we are imposing tariffs on ‘them.’ Nope. The payment comes from my pocket and yours,” said David Kotok, chairman of Cumberland Advisors. “Business doesn’t know how to plan. So it waits. Capital investment waits. And growth slows.”