On October 17, the crisis of regional banks in the United States has dragged down the stock price of banks. Two American banks have said that they have been defrauded when providing loans to funds that invest in bad commercial mortgages, heightening market concerns about the credit crisis. Zions Bancorp shares fell as much as 15%. The company disclosed that a loan underwritten by its wholly-owned subsidiary, Bank of California and Trust of San Diego, took a $50 million impairment charge. Western...