The day ahead: Tuesday


IPOs from Colony Financial and Apollo Commercial Real Estate kick off the biggest week for U.S. IPOs in nearly two years.

In other news:

*  The Federal Reserve begins its two-day open markets committee meeting.

*  World leaders meet at U.N. headquarters in New York for a one-day climate summit.

*  Lower costs for meats and other commodities are expected to help ConAgra Foods post higher fiscal first quarter profit.