There could be shortcomings with the security and paperwork behind many bank loans -- but the company that did this week's stress tests didn't have enough time to probe the issue fully.
If there is a problem with the security or the paperwork underpinning the loans, banks would lose even more money than usual when borrowers get into trouble.
BlackRock, a giant US money manager, asked two law firms to look at the issue of the security and paperwork behind Ireland's bank loans as part of the stress-test process.
The law firms highlighted several issues after looking at the issue, including the type of mortgages given to householders and what they called "missing documents".
BlackRock said that overall it didn't think the "identified issues" would radically alter the kind of figures produced this week in the stress tests. But the firm admitted it didn't have time to fully explore the issue "within the scope and timeframe of the review".
The stress tests also disclose that a large number of small business owners also have property loans that are in trouble. Small business owners often used the gains from their businesses to buy apartments and other property.
The report found that a backlog has built up in many bank branches where staff are trying to deal with small business owners who are seeking to change the terms of their loans, known as a restructuring.
Meanwhile, BlackRock might have told the banks to raise less than €24bn if there had been time to go through loans one by one instead of in batches, a review of the stress tests found.
The review by Boston Consulting Group also found that BlackRock's work on the banks was "consistently behind schedule on submitting key deliverables" to the Central Bank.
The comments were made in an appendix to the stress tests report published on Thursday. BlackRock was engaged to assess Irish banks' loan losses, while Boston was engaged to review BlackRock's work.
In its assessment, Boston said that the methods BlackRock had used to forecast loan losses were "appropriate given the mandate and time constraints".
But Boston pointed out that if BlackRock had been able to go through banks' loans one by one that would "probably have resulted in fewer conservative assumptions", and ultimately left the banks with smaller expected losses.
Boston also pointed to BlackRock falling behind schedule on the work, but said it recognised that BlackRock "encountered many difficulties extract- ing sufficient data from banks".
Overall, Boston said it "believes the approaches taken by BlackRock were satisfactory" and that the results of the stress tests were "appropriately conservative, in line with BlackRock's terms of reference".