Allied Irish Banks loses the First Trust name for its Northern Irish activities.
All activities and products of First Trust Bank will be renamed AIB in the next two years.
The Dublin-based bank said the move was due to its strategy of closer integration in its three main markets.
Customers do not have to take any action and there are no consequences for accounts or services during the rebranding.
Earlier this year, the bank announced it would put an end to the tradition of printing its own banknotes in pounds sterling.
It said that the move was a commercial decision and that the existing banknotes in June 2022 no longer paid legally.
First Trust is one of the "big four" banks in Northern Ireland.