House prices across 20 major metropolitan areas rose 3.8% in April from a year earlier, according to the latest Standard & Poor's (S&P)/Case-Shiller House Price Index (HPI). The 10-city composite HPI is up 4.6% from a year earlier: The Dallas, Denver, San Diego and San Francisco metropolitan statistical ares (MSAs) all posted six consecutive months of positive annual rates of return -- at a respective 3.3%, 4.4%, 11.7% and 18%. "Home price levels remain close to the April 2009 lows set by the S&P/Case Shiller 10- and 20-City Composite series," said David Blitzer, chairman of the index committee at S&P. "The April 2010 data for all 20 MSAs and the two Composites do show some improvement with higher annual increases than in March's report." Blitzer added: "However, many of the gains are modest and somewhat concentrated in California. Moreover, nine of the 20 cities reached new lows at some time since the beginning of this year." On a monthly basis, 18 of the 20 MSAs improved from March 2010 data. These gains were likely driven by the end of the first-time homebuyer tax credit program on April 30, according Blitzer. "Other housing data confirm the large impact, and likely near-future pullback, of the federal program," he said. "Consistent and sustained boosts to economic growth from housing may have to wait to next year." Write to Diana Golobay.