The amount of mortgage borrowers falling behind on payments flattened out since dropping earlier in the year.

The rate of borrowers moving from current to delinquent status stayed at roughly 2.5% in June, roughly half the rate seen at the peak of the foreclosure crisis.

Indeed, the rate is at its lowest level since the housing bust began.

But across all loans types – including subprime – the improvement halted since the spring, according to Bank of America (BAC) researchers (click the graph below to expand).

The roll-rate continues to trend lower but "at a more modest pace."

Still, a stability in home prices and employment could keep the post-crisis trend continuing, the bank researchers said.

But further improvement in the unemployment rate is "frustratingly slow," Federal Reserve Chairman Ben Bernanke told a Senate Banking Committee Tuesday. A host of threats – particularly Europe and the fiscal showdown in Washington – could toss the economy back into recession next year, he added.

More current borrowers called nonprofit call centers recently about financial stress. One center, the Homeownership Preservation Foundation, reported such troubled phone calls increased 70% already this year.

Still, home prices improved at a faster rate than the BofA researchers expected. Prices in hardest hit areas such as Las Vegas, Phoenix and Chicago increased by more than 20% in May. This perceived bottom will attract even more investors for the short-term at least.

"The (year-to-date) strength establishes in our view a good psychological foundation for housing to build on," researchers said.