NEW YORK — Almost one-third of U.S. homeowners who bought in the past five years now owe more on their mortgages than their properties are worth, according to Zillow.com, an Internet provider of home valuations.

Second-quarter home prices fell 9.9 per cent from a year earlier, giving 29 per cent of owners negative equity, said Zillow, the Seattle-based service.

For those who bought at the 2006 peak of the housing market, 45 per cent are now under water, it said.

The highest percentage of homeowners with negative equity were located in California. In four of the state’s metropolitan areas — Stockton, Modesto, Merced and VallejoFairfield — the number of homeowners whose mortgage debts exceeded the values of their properties topped 90 per cent, Zillow said.