U.S. stocks traded lower on Monday on continued concern about the Greece situation, while firming oil prices boosted the energy sector. The Dow Transports fell more than 1 percent, with the airlines among the greatest decliners. The fast-food giant McDonald’s reported global same-store sales shrank 1.8 percent last month, which was worse than analysts had been expecting. The stock fell more than 1 percent on the news and was among the Dow laggards. In midday trade the Nasdaq dipped in and out of positive territory for the day and was the only major index in the black for the year. The top-weighted Apple (AAPL) and Microsoft (MSFT) both gained about 0.50 percent.

“The market has certainly gotten a bit bifurcated,” said Art Hogan, chief market strategist at Wunderlich Securities, noting that the indications of investors being more selective was a “very good sign.” “The biggest story out there is the lack of any concrete work in Greek negotiations,” Hogan said earlier. It’s “disappointing” for markets that “we’re not moving forward in the Greek negotiation problem.” Greece’s new leftist Prime Minister Alexis Tsipras said on Sunday in his election pledge that he would end the country’s “cruel” austerity program and ruled out an extension of international bailout. Starting Wednesday, Greek banks will not be able to use Greek government bonds as collateral in daily refinancing operations with the European Central Bank.

Shares on the Athens Stock Exchange tumbled about 5 percent on Monday.

“I think (Greece) is going to be an issue, causing volatility, not a huge selloff,” said Randy Frederick, managing director of trading and derivatives at Charles Schwab. The CBOE Volatility Inde (^VIX)x, widely considered the best gauge of fear in the market, has come off the 20-level to more comfortable levels of 16-17, he said. The VIX held near 18 on Monday. The energy sector led sector gains on the S&P 500. Chevron (CVX), Caterpillar (CAT) and Exxon Mobil (XOM) were among the few blue chips trading higher. The Organization of the Petroleum Exporting Countries (OPEC) hiked its demand forecast for 2015, predicting that low prices would help boost demand later in the year. However, the organization still said in a report on Monday that oil demand growth was “yet to show any signs of accelerating.” Read More Forget rally, oil heading lower: Analyst Oil rose nearly 3 percent to around $ 53 a barrel, while Brent held above $ 58 a barrel.

“If you stabilize oil prices at these levels it lessens fear of deflation. I think that’s an underlying positive for the market,” said Peter Cardillo, chief market economist at Rockwell Global Capital.

Over the weekend, China reported that exports fell 3.3 percent in January from a year earlier, while imports slumped by 19.9 percent, both missing expectations by a wide margin, and resulting in a record monthly trade surplus of $ 60 billion. “That of course is a negative because it weighs on the global economy,” Cardillo said. “I think that probably may give investors (a buying) opportunity here in a choppy to negative session.” Read More Eyes on the Fed, Greece after strong jobs report U.S. stocks closed down on Friday, but ended the week significantly higher on stabilizing oil prices, amid continued concerns over Greece and a strong jobs report that renewed the possibility of an earlier Fed rate hike. The Dow Jones Industrial Average (Dow Jones Global Indexes: .DJI) traded down 69 points, or 0.39 percent, or 17,753, with Travelers (TRV) leading decliners and Caterpillar the greatest blue chip advancer. The S&P 500 (^GSPC) traded down 2 points, or 0.09 percent, at 2,052, with health care the greatest laggard and energy leading four advancing sectors. The Nasdaq (^IXIC) traded up 2 points, or 0.04 percent, at 4,746.

Read More New York trader: Beware S&P 500’s right shoulder Advancers were a step ahead of decliners on the New York Stock Exchange, with an exchange volume of 300 million and a composite volume of 1.5 billion as of 12:20 p.m. The U.S. 10-year Treasury note yield rose to 1.94 percent. The U.S. dollar traded lower against major world currencies.

Crude oil futures traded up $ 1.36, or 2.65 percent, at $ 53.06 a barrel on the New York Mercantile Exchange. Gold futures pared gains to trade up $ 4.90, or 0.40 percent, at $ 1,239.60 an ounce around 12:59 p.m. Microsoft was inundated with more than $ 26 billion of investor orders for a jumbo bond deal on Monday with buyside accounts attracted by what they described as extraordinarily generous new issue concessions for such a marquee issuer. Apple plans to hold its first Swiss franc-denominated bond sale, according to the Wall Street Journal. The paper said the sale could come as soon as tomorrow, and the Goldman Sachs and Credit Suisse will manage it.

Hasbro reported quarterly earnings of an adjusted $ 1.22 per share, beating estimates by one cent, with revenue slightly below forecasts. Hasbro said foreign exchange hurt fourth quarter revenue by more than $ 75 million dollars. Separately, Hasbro raised its quarterly dividend to 46 cents per share from 43 cents. Masco (MAS) earned an adjusted 24 cents per share for its latest quarter, four cents above estimates, with revenue slightly below Street forecasts. The maker of building products said it is benefiting from cost controls and better productivity. CNA Financial (CNA), Lowes’s largest subsidiary, reported a 10 percent fall in profit due to lower net written premiums.

Read More Apple has 90% of smartphone profit Computer Sciences (CSC), Credicorp (:BAP-PE) and NetEase (NTES) are all due after the bell.

Reuters and CNBC’s Peter Schacknow contributed to this report.

On tap this week: Monday Earnings: Computer Sciences Tuesday Earnings: Coca-Cola, CVS Health, UBS, MolsonCoors Brewing, Reynolds American, Wyndham Worldwide, Dean Foods, Akamai 8:20 a.m.: Jeffrey Lacker speaks 9:00 a.m.: NFIB Small Biz Optimism Index 10:00 a.m.: JOLTS 10:00 a.m.: Wholesale trade 1:00 p.m.: 3-year note auction Wednesday Earnings: Mondelez Intl., PepsiCo, TimeWarner, Lorillard, Mosaic, Thomson Reuters, AOL, Generac, Baidu, Cisco Systems, MetLife, Applied Materials, CenturyLink, NetApp, Nvidia, Sun Life Financial, Tesla Motors, TripAdvisor, Whole Foods, Cheesecake Factory, FireEye, Panera Bread, Pilgrim’s Pride, Select Comfort 7:00 a.m.: Mortgage applications 8:00 a.m.: Fed’s Fischer speaks 10:30 a.m.: Oil inventories 1:00 p.m.: 10-year note auction 2:00 p.m.: Treasury budget Thursday Earnings: Total, Advance Auto Parts, CreditSuisse, Dr Pepper Snapple, Hospira, Kellogg, McGraw-Hill Financial, Nielsen, Avon Products, AIG, CBS, DaVita, Digital Realty Trust, Kraft Foods, RepublicServices, Groupon, King Digital, Regal Entertainment, Shutterfly, Zynga 8:30 a.m.: Jobless claims 8:30 a.m.: Retail sales 10:00 a.m.: Business inventories 10:30 a.m.: Natural gas inventories 10:30 a.m.: Draghi speaks in Brussels 1:00 p.m.: 30-year bond auction 4:30 p.m.: Fed balance sheet/money supply Friday Earnings: ArcelorMittal, Brookfield Asset Management, J.M. Smucker 8:30 a.m.: Import and export prices 10:00 a.m.: Consumer sentiment More From CNBC.com: Lew: US economy needs wage growth Ice Bucket Challenge: 6 months later Getting divorced without breaking the bank