Santander is reportedly considering a take-over of Bank of Ireland.
The Spanish bank, which owns Abbey National in the UK, is refusing to comment on the matter, or reports that it may be eyeing up US bank Washington Mutual.
It follows reports this morning that Anglo Irish bank is considering making a bid for Irish Nationwide Building Society.
Analysts say Bank of Ireland needs to bulk up if its to become a significant player in the UK mortgage market.
That is despite the fact that its UK mortgage book of €34bn is considerably bigger than its Irish mortgage book.
At the beginning of the year, Santander held talks with Alliance and Leicester in the UK about a possible take-over.
If that went ahead, it would further marginalise Bank of Ireland's operation there.
Bank of Ireland has in the past attempted mergers with both Alliance and Leicester and Abbey National, the latter eventually being taken over by Santander.
Meanwhile, it is understood that Anglo Irish Bank is in tentative talks with the Government and the Regulators here over a proposed bid to take over Irish Nationwide.
Anglo is reluctant to go ahead with the deal without the Government's blessing.