The Dow Jones industrial average was up six points, less than 0.1 percent, at 16,484 in midday trading Monday.
The Standard & Poor's 500 index fell a point, or 0.1 percent, to 1,840. The Nasdaq composite fell five points, or 0.1 percent, to 4,150.
With just two days left in 2013, the S&P 500 is on track for an annual gain of 29 percent, the biggest since 1997. With dividends included, it's up 32 percent.
Crocs jumped $2.34, or 18 percent, to $15.67 after the shoe maker said it was getting a $200 million investment from the private equity firm Blackstone.
The yield on the 10-year Treasury note slipped to 2.98 percent.