Almost Half of Homes in New York and D.C. Are Now Losing Value

The values of 45 percent of houses in both the Washington and New York areas slumped by at least 2 percent in June from a year earlier, according to a new index created by Allan Weiss, co-founder of the Case-Shiller home price indexes. In June 2014, only 15 percent of Washington residences dropped in value, while 20 percent fell in New York. Because the index is of only single-family homes, it doesn't include Manhattan. More properties also were in decline in Los Angeles, Chicago, Phoenix and Miami. 

A steady rise in U.S. home prices since the bottom of the market combined with weak income growth has made housing less affordable, especially in big cities. Credit remains tight and demand is now being driven primarily by buyers dependent on mortgages, as foreign buyers and investors pull back from the market. 

"What happens in any bull asset bubble such as what we've seen is you run out of buyers," said Chris Whalen, senior managing director at Kroll Bond Rating Agency Inc. and an advisor to Weiss. "It's hard to get deals done if the bottom third can't get a mortgage."

Weiss, founder and chief executive officer of Weiss Residential Research LLC, based in Natick, Massachusetts, introduced his repeat-sales index last year. It provides a value for every home in the markets the firm covers based on similar homes that sold nearby. 

While an average home in a city may be rising, many homes within the area may be losing value instead, he said. A larger share of homes with declining values could be an early warning that the market may be in danger, he said. 

"If you have a market where every house is rising and you hear the news that the housing market is up, you're correct in applying it to your own home," Weiss said. "However, if you are in a market where 60 percent of houses are rising, you have a 40 percent chance of misunderstanding what's going on with your house."