The recent sabre rattling by ACCC boss Graeme Samuel at the diminishing banking competition in Australia looks set to intensify if recent rumours that National Australia Bank is poised to purchase ING Bank Australia ring true.

ING Bank, better known as the online brand ING Direct, has $34.7 billion in residential lending and $16.8 billion in retail deposits and is sitting fifth in market share in both categories for banks operating in Australia, as reported in CoreData’s Australian Mortgage Report and Australian Cash Report.

With ING sitting behind the existing big four, the speculated move by National for the group would further increase the big four’s stranglehold to 75.8 per cent of the total outstanding mortgage value in Australia, up from the present 72.4 per cent and if ING Australia remained a subsidiary attached to its Dutch parent ING Group.

Retail deposits plays out a similar scenario, with the big four potentially increasing to 76.0 per cent of retail deposits of those held by Australian Deposit-taking Institutions (ADI’s), up from 72.5 per cent.

Suncorp with $28.1 billion in residential lending would then move into fifth spot in terms of market share behind the big four heavyweights, with Bendigo & Adelaide sixth based on its present $25.9 billion in mortgages.

With regards to retail deposits, Bendigo & Adelaide with $16.3 billion would occupy fifth place, followed by Bank of Queensland with $13.8 billion and Suncorp $13.4 billion in the event that NAB snaps up ING.

Samuel will have the juxtaposed position on one hand of not wanting the big four banks controlling an increased mortgage and deposit market share, but on the other hand if an Australian bank can strengthen it’s position at the expense of a foreign bank, then perhaps why not?