The Halifax brand is being scrapped after 173 years, with all customer accounts to be rebranded to Lloyds.
Lloyds Banking Group, which has owned Halifax since 2009, confirmed the move after reports in May said it was considering phasing out Halifax as a standalone brand.
Lloyds said it remained committed to the town of Halifax and the wider Yorkshire and Humber region, where 3,000 staff are based at its Trinity Road office.
Lloyds Banking Group's chief executive of consumer relationships Jas Singh said very little would change for customers.
"As Halifax changes to Lloyds, our Halifax customers will keep everything they know and love today - the same fantastic app design, the same friendly faces in our branches - even the same sort code and account number," he said.
No job cuts are being announced as part of the shake-up, and Halifax branches will either be rebranded to Lloyds or shifted to a nearby branch throughout 2027.
It is understood the decision was rooted in efforts to simplify the group's portfolio, with the distinction between Halifax and Lloyds seen as becoming less prominent in recent years.