IBRC has filed documentation to start legal action against the former boss of Irish Nationwide Michael Fingleton and five former senior Irish Nationwide figures.
The five are former chairman Michael Walsh, and former directors Terence J Cooney, David Brophy, Cornelius P Power and John S Purcell.
The two plenary summonses were filed in the High Court Office today.
The first relates to Mr Fingleton, while the second relates to the five former directors.
By filing the summonses now, IBRC will be able to take legal action against Mr Fingleton and others in due course, and will not run out of time under the statute of limitations.
It is understood that the issues involved could go back to 2006.
The move follows a probe into Irish Nationwide carried out some years ago by Ernst and Young and McCann Fitzgerald.
IBRC had been asked to examine the result of that investigation, which had been passed on to the Minister for Finance and the Financial Regulator.
Sources described today's summonses as "protective" - to avoid running out of time to take legal action against the former Irish Nationwide personnel.
It is speculated the legal action could in relation to alleged breach of contract, breach of fiduciary duty and breach of duty of care.
Smaller IBRC reports lower loss
IBRC, the former Anglo Irish Bank, this morning reported a pre-tax loss of €873m for the year to the end of December.
This compares with Anglo Irish Bank's record loss of €17.7 billion in 2010. IBRC also includes Irish Nationwide Building Society.
For 2011, IBRC set aside a total €1.64 billion to cover loan losses, and it lost €640m on the transfer and sale of some of its assets to other institutions.
IBRC said that, when bad loan charges and sell-offs were excluded, it made an operating profit of €620m.
The bank said it had reduced staff costs by 8% during 2011, with staff numbers falling by 11% to 1,219. 210 staff were transferred to AIB. IBRC's workforce includes 183 people working directly in its NAMA division.
IBRC also said it had received a total of €42.2 billion in funding from central banks and monetary authorities.
Total assets are now €55.5 billion, though this includes €29.9 billion in Government promissory notes.
Chief executive Mike Anynsley said there had been "welcome progress" during the year, and that IBRC's focus was to maximise the return for the taxpayer.
Mr Aynsley had a base annual salary of €500,000 last year, according to the IBRC annual report. He also received a pension contribution of €125,000, relocation allowances of €203,000 and car allowance of €38,000. His total package fell from a year earlier and will fall next year, he said. Chairman Alan Dukes was paid €150,000.