Fitch ratings agency has downgraded its rating on Italy's biggest bank UniCredit and threatened to cut the ratings of seven others.
Fitch has also put several Spanish and French banks on negative watch after changes in its outlook on euro zone sovereign ratings.
In a statement, the agency said the downgrade reflects the challenges facing many banks globally, particularly in Europe.
Fitch cut UniCredit's longterm rating from A to A- and its short term rating from F2 to F1.
The seven banks put on negative watch include Intesa Sanpaolo and Banca Monte dei Paschi di Siena, the third-biggest lender in Italy.
In Spain, the eight banks on negative watch include Banco Santander and Banco Bilbao Vizcaya Argentaria.
In France, Fitch Ratings revised the outlook on Societe Generale, Groupe BPCE, Dexia Credit Local and La Banque Postale from stable to negative.