NEW YORK — U.S. stocks are opening lower after Greeks voted overwhelmingly to reject the terms of the country's latest bailout.
U.S. government bond prices rose early Monday as investors sought safe places to park money.
Aetna sank 6 percent in early trading. The company agreed last week to buy rival health insurer Humana for $35 billion.
The U.S. market is coming off its sharpest weekly decline in three months.
The Dow Jones industrial average fell 126 points, or 0.7 percent, to 17,601 as of 9:35 a.m. Eastern time.
The Standard & Poor's 500 index gave up 15 points, or 0.8 percent, to 2,061. The Nasdaq composite fell 38 points, also 0.8 percent, to 4,971.
The price of oil sank 5 percent.
The yield on the 10-year Treasury note fell to 2.29 percent.