Moody's Investor Service said it will put European banks in 15 nations under review for possible downgrade. The review will include all subordinated, junior-subordinated and Tier 3 debt ratings of 87 banks such as BNP Paribas, Societe Generale, UniCredit and other large banks.

The subordinated debt assumes that banks receive government support, thus some banks may be prone to a downgrade by one level while other ratings may be lowered by more than one level.