O'ahu home values have yet to stabilize, but a new federal report suggests that price declines may be smaller than local home resale data suggest.

The Federal Housing Finance Agency yesterday reported that single-family home values in the second quarter declined 5.9 percent on O'ahu compared with the same quarter last year.

That compares with Honolulu Board of Realtors data indicating the median price of homes sold fell 9.7 percent, to $569,500 from $636,000 in the same period.

While the federal analysis is more favorable than the Board of Realtors' report, the market is still worsening by both measures.

The FHFA's 5.9 percent decline was higher than the 4.7 percent decrease it reported for the first quarter over the 2008 first quarter, and the Board of Realtors' 9.7 percent second-quarter drop was higher than its 8.1 percent in the first quarter.

The federal report is based on sale or refinancing values of homes in the quarter compared with sale or refinancing values for the same properties a year earlier.

Because of the same-home methodology, the federal data represent relatively few transactions, but are considered by some industry followers to represent inherent property values better than median sale prices.

The median price is a point at which half the sales are for more and half for less, which is a measure influenced by the variety of homes sold. For instance, the median would be higher if newer and bigger homes make up more of the sales, or lower if more older and smaller homes are sold.

The mix factor, which can be magnified when the number of sales is relatively small, is one reason why some discount the usefulness of median resale figures.

One constraint in the federal report is that it's limited to homes bought with conforming mortgages purchased or backed by Fannie Mae or Freddie Mac, which excludes a significant part of the market financed by subprime and jumbo loans. Much of the depression in housing markets has been concentrated on properties bought with subprime loans.

The FHFA is responsible for regulating the two mortgage finance giants taken over by the federal government last year.

Out of 296 metropolitan areas, Honolulu, or O'ahu, ranked 205th, meaning 91 other areas had greater home value declines. Only 72 markets had home value gains.

The strongest market was Spartanburg, S.C., with a 3.5 percent increase. The worst market was Merced, Calif., with a 27.2 percent decline.

Part of the reason O'ahu ranks in the bottom third of the report is that many markets have already suffered severe downturns and are now rebounding, whereas O'ahu only began experiencing a modest decline last year.

The agency also reported home values by state based on same-home purchases but not refinancing. The figure for Hawai'i was down 11.7 percent in the second quarter compared with a year earlier, ranking the state fifth-lowest between Utah's 11.6 percent decline and a 15.4 percent drop in California.

Nevada was worst, with a 28 percent decrease. North Dakota had the best value change with a 2.8 percent gain. The national average was down 6.1 percent.