Moody's downgrades $64 billion of U.S. muni debt

NEW YORK/MIAMI: Moody's Investors Service on Friday cut ratings on $64 billion of municipal bonds, including debt owed by 1,675 local and state governments, because the obligations rely on 15 global banks the Wall Street credit agency sees as less steady.

Moody's on Thursday downgraded big banks such as Citigroup that provided "letters of credit, standby bond purchase agreements, and other liquidity facilities" backing $45 billion of tax-free debt.