AIB has said it will no longer offer tracker mortgages to new customers.
In a statement, the bank said the tracker product - which moves in line with the European Central Bank's main interest rate - had been under review for some time.
This is because of the high cost of funds for banks in the wholesale money markets, which have moved well ahead of the ECB rate. AIB says this makes tracker mortgages 'unsustainable'.
Existing customers with tracker mortgages are not affected. Customers who have an offer of a tracker mortgage will still be able to avail of it AIB says.
A number of other lenders have already decided to stop offering trackers to new customers.