SAN DIEGO — Home prices in the San Francisco Bay area tumbled 16 percent in March as potential buyers of expensive homes struggled to get loans, a research firm said yesterday.

The median price of a home in the nine-county area was $536,000 in March, down from $639,000 in March 2007 and down 19.4 percent from the peak of $665,000 last summer, said DataQuick Information Systems.

By comparison, the median price for a single-family home on O'ahu was $628,000 in March, a 2.4 percent decline from the same month a year earlier, according to the Honolulu Board of Realtors.

There were 4,898 new and resale homes and condos sold in the San Francisco Bay area during March, down 41.1 percent from 8,317 a year earlier. That marks the slowest March since DataQuick began keeping records in 1988.

Still, the area has fared better than other parts of the state, including the Central Valley and inland Southern California.

DataQuick reported Tuesday that Southern California home prices plummeted 24 percent in March to a four-year low.

"Most of the distress is in areas that absorbed spillover activity during the 2004 and 2005 frenzy," said Marshall Prentice, DataQuick president. "It still appears that a lot of Bay Area activity is just on hold, waiting for the mortgage markets to open back up."

The median price of homes sold in a six-county region of Southern California stood at $385,000 in March, a sobering turnaround from the previous year when values had reached a record $505,000, according to data released by DataQuick.

Southern California homes haven't sold for so little since April 2004.