Ratings agency Standard & Poors has downgraded 15 European banks, including Bank of Ireland and Deutsche Bank.
The move followed an agreement by the European Parliament on a framework preventing governments from having to bail out troubled financial institutions.
The agency downgraded the banks from stable to negative, saying extraordinary government support for them would likely diminish as regulators implement reforms.
S&P also raised its ratings on Danske Bank and Argenta Spaarbank.
Earlier this month, the European Parliament signed off on new legislation to make it easier and less costly for taxpayers to wind down problem banks, after long wrangling over rules for an industry blamed for triggering the worst economic slump in a generation.