The bank's loss is said to be largest in Irish history
Nationalised lender Anglo Irish Bank has announced what is reported to be the largest corporate loss in the history of the Republic of Ireland.
The struggling bank made a loss of 12.7bn euros ($17.2bn; £11.4bn) in the 15 months to December.
The announcement comes a day after the Irish government said it would inject a further 8.3bn euros into the bank.
Irish Finance Minister Brian Lenihan said pumping in more money was "the least worst option".
Anglo Irish said it had been an "exceptionally difficult" 15-month period since it was nationalised in January last year.
The bank found itself in severe difficulty in late 2008 following the sharp downturn in the Irish housing market. This left it facing substantial bad debts.
Mr Lenihan said on Tuesday that finding a long-term solution for Anglo Irish Bank was "by far the biggest challenge in resolving the [Irish] banking crisis".
"The unavoidable reality is that the bank has incurred losses from its large-scale property lending and needs substantial further capital," he added.
Meanwhile, European Union regulators have launched an investigation into Dublin's help for Anglo Irish, warning that the bank must draw up a new business plan and "restructure profoundly".
Anglo Irish said its bad debt write downs for the period totalled 15.1bn euros, of which 10.1bn euros would be transferred to the state-run "bad bank" - the National Asset Management Agency (Nama).
While Anglo Irish has been the bank worst hit by the crisis in the Irish banking sector, others have also been affected.
Last year the Irish government was also required to take a 25% stake in Allied Irish Banks, and 16% of Bank of Ireland (BoI).
BoI - the country's largest - reported on Wednesday that it made a loss of 1.8bn euros for the nine months to 31 December.
It said it needed to raise an additional 2.7bn euros, both privately from investment firms, but also from Nama.
As part of the fund-raising, the Irish government is converting its preference shares in BoI to ordinary shares, but expects to remain a minority shareholder.
BoI said in a statement: "The bank believes that it has a robust investment case to enable it to raise a substantial amount of the incremental capital required by the Financial Regulator from private sources, including existing shareholders."
Mr Lenihan said BoI had "a strong future".
"In recapitalising Bank of Ireland, we will secure an institution that will maintain a presence in the international capital markets, provide loan finance to individuals and businesses and support our economic recovery," he added.
The Irish government estimates that, collectively, the country's banks have a capital shortfall of up to 32bn euros.
Allied Irish Banks (AIB) has confirmed that First Trust, its bank in Northern Ireland, is up for sale as part of its efforts to raise 7.4bn euros.
The bank is transferring 23bn euros worth of loans to the Republic's National Asset Management Agency, formed to took control of toxic assets, at an average discount of 43%.
In order to raise funds to offset this shortfall, AIB is selling its divisions in the UK, Poland and the US. The company says it expects the sales to meet a substantial part of their overall need for capital.