WASHINGTON -- The source of trouble in the mortgage market has shifted from subprime loans made to borrowers with bad credit to homeowners who had solid credit but took out exotic loans with ballooning monthly payments.

The Mortgage Bankers Association said Friday that more than 4 million American homeowners with a mortgage -- a record 9 percent -- were either behind on their payments or in foreclosure at the end of June.

"The problem that policymakers and Wall Street once assured us was 'contained' to subprime mortgages has proven to be anything but," Mike Larson, a real estate analyst with Weiss Research, said in a research note.

As the economy falters and home prices keep falling, concern is building about a second wave of mortgage defaults flooding the market through 2010.

A drop in income -- whether through a lost job, divorce, death of a spouse or health problems -- is the No. 1 reason people fall beyond on their mortgages and lose their homes.

But mortgage defaults and foreclosures in many areas, especially California and Florida, can also be blamed on egregious lending practices and rampant speculation by home builders and small investors alike.

"We are unlikely to see a national turnaround until we see a turnaround in the two largest states," with the most outstanding home loans, said Jay Brinkmann, the Mortgage Bankers Association's chief economist.

The latest quarterly figures broke records for late payments, homes entering the foreclosure process and for the inventory of loans in foreclosure. The trade group's records go back to 1979.

The percentage of loans at least one month past due or in foreclosure was up from 8.1 percent in the January-March quarter, and up from 6.5 percent a year ago, using figures that were not adjusted for seasonal factors.

New foreclosures rose from the first quarter in 35 states and Washington, D.C. The biggest increases were in Nevada, Florida, California, Arizona, Michigan, Rhode Island, Indiana and Ohio.

In Ohio, 18.3 percent of the state's 207,612 subprime loans were past-due in the April-June period and 13.9 percent were in foreclosure. Among prime-loan mortgages offered to buyers with the best credit, 4 percent of 1.1 million loans were past-due and 2 percent were in foreclosure.

Pat Begg, president of the Ohio Mortgage Bankers Association, said he has seen evidence that buyers are poised to get into the market, suggesting they believe the drop in home values may bottom out soon.

For now, mortgage bankers can get ready by pre-qualifying customers who are waiting for the right time and price, he said. Thirty-year, fixed-rate mortgages are running in the 6 percent range, he said.

New foreclosures actually declined in Texas, Massachusetts and Maryland. Both Maryland and Massachusetts recently passed laws to slow the foreclosure process and give borrowers more time to catch up on their payments.

Almost 500,000 homeowners, or about 1 percent, entered the foreclosure process in the second quarter.

But for the first time since the mortgage crisis started, delinquencies on subprime adjustable-rate loans declined. While more than one out of every five homeowners with a subprime ARM is still in default, that portion dipped 1 percentage point from the first quarter to 21 percent.

What's driving up the delinquency rate now is the number of homeowners with risky, adjustable-rate prime loans made with little or no proof of the borrowers' income or assets.

More than one out of 10 borrowers with a prime ARM is now delinquent or in foreclosure. That portion, 11.3 percent, was up from 9.7 percent in the first quarter, and is expected to rise as more homeowners see their monthly payments spike.

Many of these loans allowed the borrower to pay only the interest on the loan for a fixed period. Others gave the borrower the option to "pick-a-payment," adding any unpaid interest to the principal balance.

Defaults on these mortgages, which earned the nickname "liar loans" because borrowers often did not document their incomes, are costing Fannie Mae and Freddie Mac billions of dollars. The Treasury Department has even pledged to bail out the mortgage finance companies if necessary.

With home prices plummeting, particularly in California, Nevada, Arizona and Florida, many borrowers with these exotic loans now owe more on their homes than they are worth.

Worse still, these loans reset to higher monthly payments when borrowers reach maximum debt limits -- typically around 10 to 25 percent more than the original loan.

Those resets can increase the borrower's monthly payment by more than $1,000 a month on average, Fitch Ratings said in a report this week.

And nearly half of these pay-option loans are expected to reset to higher monthly payments by the end of 2010, Fitch said.

One such borrower, Deanna Tamraz, 63, of Warminster, Pa., has been paying $1,700 a month -- which doesn't even cover all the interest -- to Countrywide Financial Corp., which refinanced her loan two years ago.

She fears she will be unable to make payments once the balance owed rises to 15 percent more than the original $260,000 mortgage, triggering a dramatic jump in loan payments. "Like a stupid person, I trusted them," she said.

Such loans "were not designed for senior citizens on limited incomes," said David Berenbaum, executive vice president of National Community Reinvestment Coalition, a Washington-based advocacy group trying to help Tamraz with her mortgage.

Rick Simon, a spokesman for Countrywide -- which was acquired by Bank of America Corp. this year -- said in an e-mail message that Tamraz's mortgage "does not qualify" for a refinance for less than the loan's original value and declined to elaborate.

• AP Economics Writer Jeannine Aversa in Washington and writer Thomas J. Sheeran in Cleveland contributed to this report.

• On the Net: http://www.mbaa.org