Following a third consecutive quarter of profit in the third quarter of 2021, the bank has decided it will relieve Capita of responsibility for its mortgage servicing operation at some point during 2022.
Capita has been responsible for the Co-op Bank's mortgage servicing operation since 2015 - a deal which was signed as part of the lender's recovery from financial crisis relating to a capital shortfall of around £1.9bn.
But the bank said that following recent strong financial results, including "strong lending performance" with £2.2bn of net residential lending in 2021, it would take this operation back from Capita.
It has pledged that its customers will be "at the heart of the process".
Nick Slape, chief executive of The Co-operative Bank, said: "We have enjoyed working in collaboration with Capita over the last six years and we are grateful for the support that Capita has given our mortgage customers.
"The Capita team has worked exceptionally hard to help our customers through the pandemic, as well as supporting new mortgage lending in a demanding market. We will continue to work closely with Capita to maintain a consistent experience for our mortgage customers whilst we move this service back into our business.
"Working with Capita has been a positive experience for us and we'd explore opportunities to work with them again in the future."