The Birmingham Midshires name is to disappear from England's high streets.
Birmingham Midshires' remaining branches will take the Halifax name
Parent company HBOS is to revamp 19 branches under the Halifax brand and close the remaining 48 branches in the Midlands, North West and South West.
The Amicus union has been told there will be no compulsory redundancies among the 470 employees.
Birmingham Midshires says the move reflects the fact that 98% of its business is conducted by telephone and internet or through brokers.
Staff affected will be redeployed within HBOS or offered voluntary redundancy.
Amicus said it regretted the move, and believed large numbers of staff would choose to leave.
The former building society - based in Pendeford, Wolverhampton - was taken over in 1999 by the Halifax, which itself merged with the Bank of Scotland as HBOS in 2001.
It specialises in the buy-to-let and self-certification mortgage market.
Birmingham Midshires was taken over in 1999
Matthew Grayson, of Birmingham Midshires, told BBC News that the decision was taken by the management of the subsidiary itself.
"It makes sense for us to concentrate on us being the UK's number one specialist mortgage lender," Mr Grayson said.
He added that most of the branches due to close were within 300 metres of a Halifax branch, and that no branch would close where it was the only provider in town.
The change to the branch network is scheduled to take place between January and March 2006.