Irish Nationwide Building Society (INBS) lent only €5m in 2009 as it grappled with the fall-out from its over-exposure to Celtic Tiger property and development lending, forthcoming accounts are expected to show.

According to an INBS source, the building society approved just €5m in mortgages and zero in commercial lending last year.

At the end of 2008, INBS had a total loan book of nearly €11bn, with €8.5bn of that in commercial property or development lending.

The building society is transferring about three-quarters of its loans to Nama, which will leave a rump of about €2bn in residential mortgages.

Last month, Nama applied a discount of 58% – the deepest of all five institutions – to the first tranche of €670m going into the agency, giving it a value of just €280m.

The government has had to inject €100m in fresh capital and €2.6bn in promissory notes to maintain the institution's capital buffers above regulatory minimum levels, such has been the damage to its balance sheet from non-performing loans.

Chief executive Gerry McGinn, who took over last year from the long-serving Michael Fingleton, has been in talks with EBS about a possible merger since December, although progress has been slow, leading many commentators to question whether a deal will emerge.