As in the housing meltdown, weakened lending standards are a big part of the story for commercial real estate. Unlike housing, however, the ill effects from weakened commercial lending standards have been camouflaged to date because they've had a longer horizon than housing did over which to implode.

"If you take a look between 2005 and 2007, the underwriting standards on both the consumer side and the commercial side were spinning out of control," said Kevin Blakely, the president of the Risk Management Association, a Philadelphia-based trade group for financial risk managers. "I think it is a bigger issue than we like to admit."

In housing, many of the loans with poor underwriting went bad within two years, when adjustable-rate mortgages were due to reset to higher interest rates and raise monthly payment costs for homeowners.

However, commercial properties carry mortgages with lives of five years or 10 years. And these loans issued from 1999 to 2007 are coming up for a rollover — refinancing under similar terms. Today's economic downturn and credit crunch makes that unlikely, however, as credit standards have tightened.

As in housing, many commercial properties have mortgages that were bundled together in pools, sliced and diced and instead of being held by banks were sold to investors as bonds and securities. Thousands of these commercial mortgage-backed securities, or CMBS, are reaching their maturity dates over the next three years. Ten-year mortgages issued in 1999 and 2000 start coming due late this year, and five-year loans issued from 2005 to 2007 come due early next year.

"If you stop and think about what is coming up for maturity over the next couple of years, either on the banks' books or CMBS, there is going to be a day of reckoning as those loans mature and they have to be rebalanced and reset to today's underwriting standards," said Blakely, who worked 17 years as a bank regulator followed by 17 years as a bank executive and risk officer.

A March study by the Wall Street arm of Deutsche Bank, Germany's largest financial institution, points to this day of reckoning. It found that the number of U.S. commercial loans that hadn't refinanced within a month of their end date had tripled.

Refinancing usually happens months ahead of the end date. Since October, commercial refinancing has dropped from a pace of more than 400 mortgages a month to fewer than 100 a month, the bank said.

The report, entitled "Commercial Real Estate at the Precipice," said that under lenient underwriting standards, 56.8 percent of existing commercial mortgages wouldn't qualify for refinancing. Using conservative standards, two thirds won't make the grade.

That suggests that lenders will have to extend loans, much like they've tried to freeze adjustable-rate residential mortgages at their original lower rate to avoid a foreclosure. Even if the commercial loans are simply extended for a year or two, however, commercial real-estate prices are forecast to keep dropping so the time bomb will be delayed not defused, the report concluded.

"In our view, much of these losses are unavoidable, even in a mass (loan) extension environment," wrote Richard Parkus, the report's author.

Forecaster Moody's Economy.com expects $375 billion in losses on the $3.5 trillion in commercial mortgage loans and securities outstanding. That a loss rate of about 11 percent, nearly twice the rate of home mortgage foreclosures, and the forecaster thinks that about $200 billion of those commercial losses are still ahead.