Wall Street analysts had been just as optimistic, and the miss resulted in a drop of more than 5% in the price of General Growth Properties stock Wednesday. "I acknowledge we made mistakes in our estimates and assumptions," said chief executive officer John Bucksbaum during Wednesday's earnings conference call. "We must improve our forecasting, and we will."

Reasons for missed expectations included lower net operating income from land sales because of deals pushed into 2006, writing off $4.3 million of capital costs in developments that fell by the wayside and lack of experience with properties acquired in the 2004 deal with Rouse Co., explained chief financial officer Bernard Freibaum.

The 40 million sf of retail properties acquired in the $7.2-billion deal were incorporated in General Growth Properties' accounting system late last year, Freibaum said during the call. "There are no accounting system issues," he added. "It's just the newness and the differences in classification and the differences in methods; it's exponentially more complex than anything we've ever done."