CHICAGO — General Growth Properties Inc. shares plummeted today after the mall owner warned it faces solvency trouble and may be forced to file for bankruptcy if it can't refinance or extend nearly $1 billion in debt due next month.

The nation's second-largest mall owner, which owns Ala Moana Center and Ward Centers, also disclosed in a regulatory filing late yesterday that it may default on certain debt obligations.

Making matters worse is another $3.07 billion in property and corporate debt slated to come due next year.

"Given the continued weakness of the retail and credit markets, there can be no assurance that we can obtain such extensions or refinance our existing debt or obtain the additional capital necessary to satisfy our short-term cash needs on satisfactory terms," the Chicago-based real estate investment trust said in filing with the Securities and Exchange Commission. "... Our potential inability to address our 2008 and 2009 debt maturities in a satisfactory fashion raises substantial doubts as to our ability to continue as a going concern."

General Growth shares fell 88 cents, or 64 percent, to 49 cents per share on the New York Stock Exchange.