Barron's reports: The US home-foreclosure rate fell in May for the first time since January. But with filings on 321,480 homes in May, it hardly suggests housing is out of the woods.

Indeed, multifamily properties have begun to feel the stress of the credit crisis, with apartment defaults spiking to 3% in recent months, versus an average monthly rate of less than a half-percent in the past eight years. And with unemployment up and rents and occupancy down since the start of the year, the numbers are poised to get worse. So says Mike Kelly, president and co-founder of Caldera Asset Management, a multifamily-real-estate consulting firm: "It's the single-family world, just two years later."

First-quarter multifamily apartment transaction volume fell more than 70%, according to Real Capital Analytics. Kelly says the situation in the $880 billion multifamily debt market is likely to get only worse, with $7 billion of such asset-backed securities coming due next year.

Meanwhile, the average capitalization rate for multifamily properties has risen by two percentage points since 2007, to about 7.5%. The capitalization rate, similar to the yield on a bond, is calculated by dividing annual net operating income by total debt and equity,

Although apartment cap rates have moved closer to those of other properties, their costs of borrowing (largely from government-sponsored entities) are typically up to 1.5 percentage points lower than for other commercial properties, Real Capital Analytics noted in its May report. Its conclusion: This is "a buying opportunity."