Moody’s Investors Service cut its ratings on four of the biggest U.S. banks after deciding the government would be less likely to help them repay creditors in a crisis, Bloomberg News reported today. Morgan Stanley, Goldman Sachs Group Inc., JPMorgan Chase & Co. and Bank of New York Mellon Corp. had their senior holding company ratings lowered one level yesterday after Moody’s concluded a review of eight U.S. banks that began in August. U.S. banking regulators have been preparing rules and procedures that seek to allow the government to wind down even the largest financial companies without providing taxpayer assistance. The plans would require investors to accept losses and could require bonds to be converted into equity capital.