Despite their misgivings, the ratings agencies kept slapping seals of approval on commercial-real-estate structures. Just as they did when rating securities containing residential mortgages, the agencies relied heavily on recent historical data, which were misleading. Such transactions are designed so that investors who take on the most risk stand to get wiped out first. What happened is that the level of cushioning shrank dramatically, meaning damage from bad loans will seep into higher-rated tranches more quickly than generally expected.

To its credit, Moody's started requiring higher levels of protection in the spring of 2007. S&P and Fitch, according to a J.P. Morgan analysis, lagged significantly—and won market share as a result. Those two will come to regret that they didn't respond faster to the Moody's move. And of course, those stuck with the paper won't be able to ignore what they bought during the frothy times, when commercial-real-estate structured finance became a big, lucrative business for Wall Street. As financial firms pushed these securities out the door, the structures took on alarming qualities.

As Todd explains, in the early part of the decade, commercial-mortgage-backed-securities deals rarely had any one loan that was so big it dominated the pool. But in recent years, the top 15 loans in a 200-loan pool could make up 40 to 65 percent of the pool's total value. In the old days, any single default wouldn't hurt a structure disproportionately. That's no longer true. Investors and ratings agencies haven't fully appreciated how hairy these structures have become, according to some commercial-mortgage experts. Todd calls this blindness to risk the agencies' and investors' "biggest mistake" with regard to commercial real estate. "You are disproportionately exposed to the largest loans.... It's been so good for so long, we don't have models set up to look at defaults properly," he says.

In recent months, as real estate developers have scrambled for funding from lenders, a standoff has developed. The banks haven't been able to find buyers for structured financial products. At some point, the banks will have to come down in price, and then they will take losses, just as they have with leveraged loans made to corporations being taken over by private equity. Since the losses haven't happened yet and since we've reached the end of a very good year in commercial real estate, Wall Street is understandably reluctant to face reality. Why take losses that will eat into this year's bonuses if you can take the losses next year, when, as everyone knows, the market will be bad?

We've seen this throughout the financial markets in 2007. This has been the season of see no evil, hear no evil, speak no evil—until you absolutely have to. But you can't hold off losses forever, as the huge write-offs at banks have demonstrated. Through the first nine months of 2007, Wachovia was by far the top contributor of loans in the commercial-real-estate-structures business, followed by Lehman, Credit Suisse, Morgan Stanley, and J.P. Morgan, according to Commercial Mortgage Alert. Now the firms are sitting on those loans, waiting to unload them. "The problem is there are no buyers. Nobody wants to take a really big loss and jump the gun too quickly," an investment professional at a commercial-real-estate investment trust told me. "There's a game of chicken going on."

A few weeks ago, a hedge fund manager emailed me a PowerPoint presentation on the commercial-real-estate market. It opened with a typically dry title: "2008 C.M.B.S. Forecast."

I clicked through to the first page, "Capital Markets." It had a picture of a derailed train. The next page, "Credit Fundamentals," included a photo of a bridge collapsing in a hurricane. Next came "Property Values," featuring an imploding skyscraper. The fourth page was "Economic Outlook"—a ship run aground on the rocks.

And the slide titled "Conclusion"? A photo of the exploding Hindenburg.