By Anora Mahmudova and Sara Sjolin, MarketWatch

Trade deficit widens as strong dollar hurts export

U.S. stocks rebounded off their lows in bumpy trading Tuesday, driven by uncertainty over the future of Greece and concerns over China's sluggish economy.

The S&P 500 briefly turned positive but pulled back to trade flat at 2,067 in a choppy trading session, where the index had tumbled by more than 20 points earlier. The S&P 500's move lower had briefly put it below a key support level last breached in October.

The Dow Jones Industrial Average was down 50 points, or 0.3%, to 17,632 but had seen a more than 200-point drop earlier. The Nasdaq Composite also pared more brutal declines to move 0.6% lower, or down 30 points, to 4,961.

Jittery trading played has been driving the market action throughout the day as European officials attempt to hash out a credible bailout plan for Greece, while the government intervention in China's stock market also has unsettled traders.

Worries among global investors over Europe and Asia could be spotted from falling government bond yields, which move inversely to bond prices, as investors sought the safety of government bonds. The yield on a 10-year Treasury note fell 9 basis points to 2.19%.

"The selloff is due to a number of factors and Greece is one of them," said Brian Fenske, head of sales trading at ITG.

"China's local stock market has essentially crashed, but that is now spilling over to U.S.-listed Chinese companies. Technology stocks are selling off due to some bad news from chip-makers," Fenske said.

"Large moves in oil and copper prices are adding to the selling pressure, which is why we are seeing big drops in materials stocks," he added.

Greece remained in the headlines on Tuesday as eurozone finance ministers convened for an emergency meeting in Brussels to discuss what's next for Greece after Sunday's referendum.

Greece's Tsipras-led government submitted a proposal on Tuesday (http://www.marketwatch.com/story/greece-arrives-at-eurogroup-meeting-without-proposal-ft-2015-07-07)with the same reform list that couldn't be discussed at the latest Eurogroup meeting before the referendum results.

Read: Eurozone officials warn of possible 'Grexit' without credible proposal from Greece (http://www.marketwatch.com/story/eurozone-officials-warn-of-possible-grexit-without-credible-proposal-from-greece-2015-07-07)

Greece's stock market will remain shut Tuesday and Wednesday (), alongside the extended closure of the country's banks, the Hellenic Capital Market Commission said. Meanwhile, Global X FTSE Greece 20 ETF (GREK) slid 3.3% after a 7% slide on Monday.

Read: Greek debt crisis: Who's meeting and when on Tuesday (http://www.marketwatch.com/story/greek-debt-crisis-whos-meeting-and-when-on-tuesday-2015-07-07)

"Investors need to get use to a shock like Greece, but there are bigger issues that investors should be concerned about," said Bruce McCain, chief investment strategist at Key Private Bank, referring to precipitous falls in China's stock market.

"When fundamentals are shaky and valuations are stretched, stock markets are vulnerable to shocks and usually it's unexpected ones that trigger large selloffs," McCain said.

U.S. data: The U.S. trade deficit rose 2.9% in May, mostly because the U.S. exported fewer aircraft and other manufactured goods. The increase was smaller than expected by economists surveyed by MarketWatch. Market reaction to U.S. trade data released ahead of the opening bell was muted.

Job openings at U.S. workplaces rose to a record high of 5.36 million in May (data go back to the end of 2000) from 5.33 million in April, the U.S. Department of Labor reported Tuesday.

Oil:Oil prices fell, after briefly ticking higher earlier in electronic trade, (http://www.marketwatch.com/story/crude-oil-struggles-to-recover-from-selloff-2015-07-07) following Monday's carnage, with the August contract for crude oil falling 1.1% to $51.94 a barrel. Brent crude for the same month inched 0.2% lower to $56.43 a barrel.

The contracts slid 7.7% and 6.3% (http://www.marketwatch.com/story/oil-tumbles-4-after-greek-voters-reject-creditors-reform-proposal-2015-07-06), respectively, on Monday. The selloff was driven by the turmoil in Greece and a potential Iranian nuclear deal, which may result in a flood of millions of barrels of oil, adding to global supplies.

Movers & shakers: Shares of Advanced Micro Devices Inc.(AMD) sank 17% after the chip maker cut its outlook late Monday (http://www.marketwatch.com/story/amd-warns-revenue-to-fall-short-on-weak-pc-demand-2015-07-06).

A. Schulman Inc.(SHLM) plunged 11% after the plastic manufacturer late Monday said it swung to a loss in the third quarter (http://www.marketwatch.com/story/a-schulman-swings-to-a-loss-cuts-forecast-2015-07-06-174854739).

Utilities stocks rallied, with the S&P 500 Utilities sub sector gaining nearly 2%. Recent 10% correction in the sector drove the valuations to attractive levels. Duke Energy Corp (DUK) jumped 2.7%, Public Service Enterprise Group Inc. (PEG) rose 2.6%.

For more on today's notable movers read Movers & Shakers column (http://www.marketwatch.com/story/amd-a-schulman-advanced-auto-parts-shares-in-focus-2015-07-07).

Other markets: Chinese stock indexes moved sharply lower (http://www.marketwatch.com/storyno-meta-for-guid), continuing the recent downbeat trend in the country's financial markets. Trading was halted in shares (http://www.marketwatch.com/story/over-20-of-listed-china-stocks-now-in-trading-halt-2015-07-07) in more than 200 mainland-traded China-traded companies during the selloff. The rest of Asian markets closed mixed. European stocks struggled for direction (http://www.marketwatch.com/storyno-meta-for-guid), with investors waiting for the latest word on Greece.

Gold fell 1.8% to $1,152.7, while the dollar rallied against most major currencies, rising 0.8% to 97.08.

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