Is this the beginning of the dreaded double-dip in home prices?

Two indices released Tuesday both posted first-quarter declines in home values across the United States, with  S&P Case-Shiller’s national data showing a 3.2% drop and the Federal Housing Finance Agency (FHFA) posting a 1.9% slide, compared to the previous quarter.

“The housing market may be in better shape than this time last year, but, when you look at recent trends, there are signs of some renewed weakening in home prices,” observed David M. Blitzer, chairman of the index committee at Standard & Poor’s.

Patrick Newport, U.S. economist at IHS Global Insight in Lexington, Mass., agreed. “In our view, the housing glut and foreclosures will drive the national Case-Shiller index down another 6% to 8%, with prices bottoming in 2011,” he wrote in a research note Tuesday.

Both the Case-Shiller and FHFA indices track home values, but they are calculated differently. Case-Shiller focuses on the 20 largest metro housing markets and includes homes purchased with jumbo loans, which often results in more dramatic home price changes than the FHFA index. FHFA’s figures are based on the purchase prices of homes with loans owned or guaranteed by government-sponsored enterprises (GSE) Freddie Mac and Fannie Mae in all 50 states.

In terms of the more frequently covered monthly numbers, Case-Shiller’s 20-city composite index slipped in March, dipping 0.5% compared to the previous month.  (This index covers Boston, Chicago, Denver, Vegas, Los Angeles, Miami, New York, San Diego, San Francisco, Washington, D.C.; Atlanta, Charlotte, Cleveland, Dallas, Detroit, Minneapolis, Phoenix; Portland, Ore.; Seattle, and Tampa.)

On an annual basis, though, home values for these 20 markets were 2.3% higher in March than the same month one year ago. The big winners? San Francisco, with a 16.2% year-over-year jump, and San Diego, where prices have risen for 11 consecutive months, resulting in a 10.8% annual increase. Las Vegas, however, continues to struggle with home values, posting a 12.0% annual drop in March, according to Case-Shiller.

The FHFA’s monthly home price index, which tends to show less fluctuation than the Case-Shiller figures, actually reported a small improvement (0.3%) in March. Year-over-year though, the FHFA index declined 2.2% compared to March 2009.

Regionally, only the Pacific region (Hawaii, Alaska, California, Washington, and Oregon) recorded an annual gain in March, rising 3.1%, according to FHFA data. The weakest performance occurred in the Mountain region, with a 5.9% annual drop. This region covers Arizona, Colorado, Idaho, New Mexico, Montana, Utah, Wyoming, and of course Nevada, where the housing  and foreclosure crisis has been particularly acute.

Alison Rice is senior editor, online, at BUILDER magazine.

Learn more about markets featured in this article: Los Angeles, CA, Portland, OR, Phoenix, AZ.