House prices spread over 25 metropolitan statistical areas (MSAs) rose 3% in June, according to the monthly index compiled by Radar Logic. Prices rose in 23 of the 25 metropolitan areas tracked for the index. The Boston MSA experienced the largest monthly gain of 6.5%, followed by Denver at 5.1%. Only the Seattle and Milwaukee MSAs experienced a decline since May, slipping 1.6% and 0.2% respectively. Radar Logic found all MSAs came in below their year-ago levels of price per square foot -- the measurement used to neutralize the exaggerating effects of house size. Year-on-year declines ranged from -2.9% in Philadelphia to -32.1% in Las Vegas. In the first half of 2009, however, not only have prices gained, but the sales activity has shifted toward more expensive neighborhoods. Radar Logic found home sales have become a larger share of total sales in each of the 25 MSAs. "The stabilization and subsequent uptick in home prices in the first half of 2009 indicates a return of demand on the part of buyers, and the shift in the mix of sales toward more expensive neighborhoods sheds some light on who the buyers are," Radar Logic says in the report. "Given the shift in sales toward homes in expensive neighborhoods, first-time home buyers may not be driving demand, particularly given the conservative lending environment." The trend toward more expensive housing may indicate a return of investor confidence, Radar Logic said. If investor demand once again drives the housing market, the report notes, the current level of price recovery "could be resilient to the effects of a double-dip recession." Prices in many metropolitan markets continued to rise into July, according to another pricing index released last week. The Altos Research/Real IQ 10-city composite index rose 0.9% in July after gaining 1.2% in June. The slowed gain in prices signals a traditionally slow fall and winter season, Altos Research said. The index, which tracks listing prices, found monthly increases in 15 of 26 major metropolitan markets in July, with all 15 showing the third consecutive month of price gains. Listing prices gained the most (6.1%) in San Diego in July, followed by San Francisco (4.5%). Las Vegas experienced the worst monthly slip in listing prices (-1.8%), followed closely by Salt Lake City (-1.4%) and Chicago (-1.3%) Listing inventory declined in 17 of 26 markets, which Altos Research said would help the markets as they enter a seasonally slow period. Write to Diana Golobay.