As of June 30, an analysis by Zillow shows that 23.8 percent of U.S. homeowners with mortgages — or about 12.2 million households — still owe more than their residences are worth. A sizable increase in property values has pulled 3.2 million homeowners above water on their mortgages in just the last year. However, that pace will slow if the rate of appreciation ebbs. Even with the rapid home price gains these past 12 or so months, Zillow notes that 57 percent of underwater homeowners carry mortgage debt that is 20 percent or more what their homes are worth. It will be years before they regain equity, even with home values continuing to rebound. Las Vegas continues to have the most deeply underwater homeowners of the top 30 markets tracked by Zillow. Nearly 13 percent of mortgaged homeowners in Sin City owe twice or more what their house is worth. Miami ranks second with 8.7 percent of mortgaged homeowners in that situation, followed by third-place Detroit at 8.2 percent. | Read More