US stocks tumbled more than 2 percent on Tuesday after a proposed Greek referendum threatened to upend a European bailout plan to contain the sovereign debt crisis. Analysts said if Greek voters reject the unpopular bailout, it would result in a "hard default" by Greece, causing bigger losses for banks and raising the threat of systemic risk.
The Dow Jones industrial average dropped 273.40 points, or 2.29 percent, to 11,681.61. The Standard & Poor's 500 Index lost 32.38 points, or 2.58 percent, to 1,220.92. The Nasdaq Composite Index tumbled 76.34 points, or 2.84 percent, to 2,608.07. Stocks struggled to hold a key technical level surpassed after equities posted their best month in 20 years in October. US bank shares were lower, with the KBW bank index off 4 percent. Morgan Stanley tumbled 9.4 percent to $15.98.