Thirty-one percent of U.S. homeowners with mortgages, or 15.7 million of them, were underwater on their mortgages in the first quarter of 2012, even though home values were on the rise, the real estate website Zillow reported this week.
* Number of troubled mortgages up 8 percent since end-2011 * Unemployment, falling house prices make repayment tougher * Big risk that losses exceed stress test results-analyst (Adds quotes, details) DUBLIN, ...