Today and for the immediate future, look at maybe 60% to 65%, and "some amortization," Shanahan says. "There's going to be some conservatively underwritten rents on buildings, but you are not going to go back to a model that had reserves to pay debt service that couldn't be covered by cash flow."

Looking back over the highly financed past decade, the report notes that 14 assets, or around 60% of all '08 transactions by dollar volume, were forced sales, averaging $707 million. That compares to an average size of $135 million for non-forced sales. In fact, the report says that 57% of '08 office sales volume was attributable to the sale of 10 office buildings by Macklowe Properties, or more specifically, by its lender, Deutsche Bank.

Putting into historical perspective the sheer number of sales that were forced by lenders so they could recover capital, Shanahan says the early 1990s would be the most comparable situation. "You had a lot of forced sales back then, but the big difference was you could still get a loan," he tells GlobeSt.com, adding that the positive differentiator between then and now is the absence of large amounts of new office construction over the past two decades. For the record, in 1992, Manhattan's vacancy rate reached 18.5%.

Shanahan says "it would be 'nice to hear' they aren't going to go with all the World Trade Center footage as planned. If they stretch it out a little bit, that would be good news for Downtown." The four towers under way at the Trade Center--the Port Authority of New York and New Jersey's Freedom Tower, and Silverstein Properties' Towers 2, 3 and 4--will add a total of 10.5 million square feet of office space to a submarket that has been seriously impacted by the upheaval in the financial services sector.

He says what Downtown is lacking at the moment by comparison to Midtown is "definition. You have a lot of question marks surrounding some of the bigger tenants as to exactly what's going to happen. When you have uncertainty, people tend to not make decisions."

The report says foreign investors accounted for 51% of 2008 office sales volume, an increase over the typically "less than 20%" of past years' transaction figures. "A large part of that percentage was driven by the General Motors building and Paramount's purchase of 1301 Ave. of the Americas and 31 W. 52d St., all considered offshore buys, "he says. Macklowe's General Motors building at 767 Fifth Ave. was purchased by a partnership of Boston Properties and Dubai-based Meraas Capital, while the Paramount Group is German-owned.

"We're seeing sources of offshore capital that we haven't seen in a decade coming into the market and doing research," Shanahan says. He adds that this will likely continue since Manhattan is "probably the safest market in the world."