By Rick Green Nov. 16 (Bloomberg) -- U.S. banks may see 10 percent of their $1.1 trillion in commercial property loans go sour and regional lenders could face credit downgrades as the impact grows, according to Fitch Ratings. The data donât include $500 billion of construction loans, which are subject to even more risk, Fitch said in a statement today. Small and mid-size regional lenders are more vulnerable than the four biggest U.S. banks, none of which has commercial property loans exceeding 10 percent of their total, Fitch said. http://www.bloomberg.com/apps/news?pid=newsarchive&sid=aOvWVhV1Zxj4