A growing number of U.S. homeowners owe more than their properties are worth after prices extended their two-year decline in the first quarter, Zillow.com said.

Almost 21.8% of all owners were underwater as of March 31, the Seattle-based real estate data service said in a report today. At the end of the fourth quarter, 17.6% of homeowners owed more than their original mortgage, while 14.3% had negative equity three months earlier.

bloomberg.com, Wall Street Journal