US stocks fell in early trade Monday on worries about a potential Greek debt default after talks between Greece and creditors collapsed over the weekend.
About 35 minutes into trade, the Dow Jones Industrial Average stood at 17,750.53, down 148.31 points (0.83 percent).
The broad-based S&P 500 shed 15.92 (0.76 percent) to 2,078.19, while the tech-rich Nasdaq Composite Index sank 51.35 (1.02 percent) to 4,999.75
Negotiations between Greece and creditors ended in acrimony Sunday as Athens seeks needed bailout funds to meet a deadline to pay 1.6-billion-euro ($1.8 billion) to the IMF at the end of the month.
Tensions remained high Monday, with Greek Prime Minister Alexis Tsipras accusing creditors of "looting" as they pressure Athens to further trim its pension system.
United Technologies fell 2.5 percent as it announced it would separate its Sikorsky helicopter business. The industrial conglomerate and defense contractor said it would decide whether to sell the unit or spin it off by the ened of the third quarter.
Target rose 1.7 percent on news it will sell its pharmacy and clinic business for about $1.9 billion to CVS Health. CVS Health will acquire more than 1,660 pharmacies across the US and operate them as a store-within-a-store within the big-box retailer. CVS Health gained 0.4 percent.
Chinese online marketplace Alibaba added 0.1 percent following reports it will launch an online video service in China modelled on Netflix. Netflix fell 2.5 percent.
Homebuilders Ryland Group and Standard Pacific surged on news they are combining to create a company with a market capitalization of $5.2 billion and an enterprise value of $8.2 billion. Ryland advanced 6.0 percent, while Standard Pacific added 6.2 percent.
Shares of Dealertrack Technologies, which provides software to auto dealers and lenders, jumped 57.5 percent higher on news it will be bought by Cox Automotive for $4 billion. Cox owns Kelley Blue Book and provides marketing and software services to the auto industry and consumers.
Chipmaker Micron Technology shed 4.6 percent following a downgrade by Morgan Stanley, which said high product inventories are depressing prices, leading to weakness in 2015 and uncertainty for next year.
Bond prices rose. The yield on the 10-year US Treasury fell to 2.33 percent from 2.39 percent Friday, while the 30-year dropped to 3.06 percent from 3.10 percent. Bond prices and yields move inversely.