TransUnion LLC, which analyzed about 27 million consumer records in its database, predicted that the proportion of consumers with mortgages that are 60 days or more past-due will hit 7.17% in the fourth quarter of 2009.

That would be the highest level reached since the Chicago credit bureau -- which is releasing the data on Tuesday -- first started tracking these statistics in 1992. It compares with an expected delinquency rate of 4.67% at the end of 2008.

The big culprit is adjustable-rate mortgages that were underwritten several years ago, when lending standards were loose.

Now, many of the initial teaser rates on these loans are expiring and resetting to higher interest rates and higher loan payments.

"There are a lot more loans that will be resetting throughout 2009 through 2011," says Ezra Becker, principal consultant in TransUnion's financial-services group, who notes that rising unemployment and depreciating home values are other contributing factors. "There may be an ongoing flow of consumers who may now be able to pay their mortgage but may not be able to a year from now."

Mortgage delinquencies are likely to peak in the first quarter of 2010 as today's new loans, which have tighter underwriting standards, take effect, he says.

TransUnion also predicted that credit-card delinquencies would rise, though not nearly as sharply. By the end of this year, the ratio of credit-card borrowers who are 90 days or more delinquent on one or more of their credit cards is expected to reach 1.09% -- roughly the same levels reached at the end of 2007, and flat with third-quarter levels -- according to TransUnion.

However, as conditions worsen, the delinquency rate is expected to climb to 1.37% by the end of 2009, or roughly the same levels reached in the fourth quarter of 2007.

Credit-card delinquencies are lower than mortgage delinquencies in part because credit-card lenders have more ways to control the potential losses, such as reducing customers' credit lines.

And while delinquencies are likely to climb, they aren't expected to hit historic highs, such as when they hit 1.89% in the fourth quarter of 2002, when consumers were struggling through a recession and the aftermath of Sept. 11.

"We are really going to see issues throughout all of 2009," Mr. Becker says.

"Even when the economy starts to recover, there's a delayed effect in how consumers start to respond. If a consumer is unemployed and goes into delinquency, when they get a job they're not going to start repaying immediately. They have to build up their funds."