by Calculated Risk on 6/08/2008 10:00:00 AM

From BusinessWeek: The Next Real Estate Crisis

[T]he next wave of foreclosures will begin accelerating in April, 2009. ... hundreds of thousands of borrowers who took out so-called option adjustable-rate mortgages (ARMs) will begin to see their monthly payments skyrocket as they reset.
...
According to Credit Suisse, monthly option recasts are expected to accelerate starting in April, 2009, from $5 billion to a peak of about $10 billion in January, 2010.
...
The loans automatically recast after five years, but many will recast sooner as loan balances hit specific principal caps—typically between 110% and 125% of the initial loan amount.

Click on image for Business Week graph in new window.

This graph from Credit Suisse (via Business Week) makes a key point. Many of the Option ARMs will recast sooner than originally scheduled, because the loan amount will have hit the principal ceiling (usually 110% of the original loan amount).

Tanta explained this in Negative Amortization for UberNerds:

[Once the loan hits the principal ceiling], the loan must become a fully amortizing loan—no more minimum payment allowed, all payments must be sufficient to pay all interest due and sufficient principal to amortize the loan over the remaining term.

The percent of original balance limitation, in other words, marks the day that neg am is no longer an option for the borrower, and the loan has to start paying down principal from here on out—the borrower is “caught up,” and never again allowed to “get behind.”
...
Note that the loan remains an ARM, even though it is now no longer a neg am ARM. That means that the borrower’s payment can still increase or decrease at future rate change dates. It will simply be, from here on out, an increase or decrease from one fully-amortizing payment to a new fully-amortizing payment.
emphasis added

What matters for the housing market is the gray bars - and we are just starting to see the impact on delinquencies of homeowners moving from NegAm payments to fully amortizing payments on their Option ARMs.

And, finally, the blue bars tell us when these homeowners obtained their loans - usually 5 years before the scheduled recast. Since the peak is in 2011, we know that most of these homeowners bought or refinanced from 2005 through early 2007. Therefore, with falling house prices, most of these homeowners are underwater (owe more than their homes are worth), and selling or refinancing will not be a viable alternatives.