In the wake of that success and as a result of it, however Standard & Poor's has placed Vornado Realty Trust and Vornado Realty LP on CreditWatch with negative implications. Securities valued at $450 million are affected. Uncertainties about how the deal will be financed and the formidable challenges involved in managing the complex were cited by S&P as factors in its decision.

Although the majority of the $3.25 billion will be paid out over nearly a century, the size of the package, 10 million sf, is large relative to Vornado's current portfolio of 15 million sf. S&P says it will try to meet with the firm's management to learn details of the transaction and get an update on its other businesses, which include merchandise marts, retail properties and temperature-controlled logistics.