National Irish Bank has reported a net loss of €49m for the nine months ending September 2008.
This compares with a profit of €11m the same time last year.
The bank, owned by Denmark's Danske Bank, said its loan impairment charges increased to €94m.
NIB said this reflected the very sharp downturn in economic and market conditions and said that those conditions were set to continue.
The bank said that most of the loan impairment charges related to provisions while actual loan write-offs amounted to €3.9m or 0.05% of average loans.