Moody's has cut the credit ratings of six German banks and three in Austria.
The biggest bank affected was Commerzbank, Germany's second-biggest lender, which was cut from A3 to A2.
The BBC reports the rating agency delayed a decision on the rating of Germany's biggest bank, Deutsche Bank.
The six German banking groups affected were Commerzbank, DekaBank, DZ Bank, Landesbank Baden-Wuerttemberg, Landesbank Hessen-Thueringen and Norddeutsche Landesbank.
In Austria, the agency downgraded Erste Group Bank, UniCredit Bank Austria and Raiffeisen Bank International.
Moody's also cut the rating of the German unit of UniCredit, an Italian bank.
The downgrades were part of a wider review of 114 European banks announced in February. Moody's notes that a number of factors caused the ratings of many German banks to decline by less than for other European banks.