The High Court has heard the two-year probe into Anglo Irish Bank requires more time to process the vast number of documents seized.
The joint investigation by the Gardaí and the Director of Corporate Enforcement (ODCE) is looking at five matters, including the bank's issuing of loans to former directors, and a deposit arrangement between the bank and Irish Life and Permanent in September 2008.
More than one million electronic records have been seized since February 2009 as part of the investigation.
A report has been sent to the DPP in relation to Anglo's provision of money to persons to enable them to buy its shares, but this strand of the investigation is still only 90% complete.
Files have also been sent to the DPP in relation to a loan by Anglo to a former director and in relation to the deposit arrangement between the bank and Irish Life and Permanent in September 2008.
Mr Justice Peter Kelly has asked whether the investigation is ever going to reach an end. He will decide whether to extend its timeframe on Tuesday.