Regions Financial ( RF) posted a wider-than-expected quarterly loss that the bank blamed on the need to set aside capital for the rising number of defaulting loans on its books -- weighing on the bank's already depressed stock price Tuesday.Known as loan-loss provisions, the amount ballooned over the course of the most recent quarter by more than 100% to $912 million, as of the end of June. At the end of the first quarter, provisions stood at $425 million, and in the year-ago second quarter at $309 million. Since the bank does business in the South, it has much at risk in the collapsed Florida real estate market, for example. As a result, the Birmingham, Ala.-based Regions, which operates a chain of retail banks across the Southeast, said it lost $188 million, or 28 cents a share in the second quarter, below analysts' expectations of 22-cent loss. A year ago, the company posted a profit of $77 million, or 11 cents a share. Investors sold off shares of the bank Tuesday in response. Regions stock was trading down in morning action at 12%, or 49 cents, at $3.55, on volume of 47 million shares. Average daily turnover is 50 million. Regions boss Dowd Ritter tried to put a good face on the bank's performance in the second quarter. "While we do not want to downplay the impact of the increase in credit costs," Ritter said in a prepared statement, "this should not overshadow the strong performance of our core business, particularly our sustained growth in households and customer deposits and the stabilization of the net interest margin."