The Dow Jones industrial average is down 11 to 13,146. The Standard & Poor's 500 is up two to 1,413. The Nasdaq composite index is up nine to 3,079.
Over the weekend, Germany's economy minister and finance minister said separately they didn't want to give Greece more time to implement the spending cuts that Germany has demanded.
The head of the German central bank repeated his opposition to a plan for Germany to buy bonds to try to lower borrowing costs for weaker European countries.
Shares of Hertz and Dollar Thrifty are both up after Hertz announced it would buy its rival. Luxury jeweler Tiffany is up despite missing Wall Street expectations for its quarterly earnings.