The agency set state banks National Bank of Egypt, Banque Misr and Banque Du Caire, as well as privately owned Commercial International Bank, to CAA1 from B3, Moody's said in an investor note seen by Reuters on Wednesday.
It also downgraded Bank of Alexandria, a subsidiary of Italy's Intesa Sanpaolo, to B3 from B2.
The downgrades reflected the operating environment and the sovereign's weakened creditworthiness, Moody's said.
On Thursday, Moody's downgraded Egypt's sovereign credit rating by a notch to 'Caa1' from 'B3', citing the country's worsening debt affordability.
The asset quality, earnings and capital buffers of the banks "may challenge their ability to meet foreign currency liabilities as they fall due," Moody's said.
"The banks' high sovereign exposure, mainly in the form of government debt securities, also links their credit profile to that of the government," it added.
(Reporting by Nadine Awadalla and Patrick Werr, Editing by Louise Heavens, William Maclean)
