Coventry Building Society has completed the acquisition of the Co-operative Bank.

The deal, estimated to be valued at £780m, will take Coventry’s total assets to £89bn and 4.5 million members and customers across the UK.

Co-op Bank has become a subsidiary of Coventry Building Society, and the combination of the two firms will see the 152-year-old bank brought back under mutual ownership.

In a message sent to customers and members of both organisations, CEO of the new group, Steve Hughes, said: “Bringing together our two values-driven organisations will result in a mutually owned business that’s deeply passionate about its members, customers and communities.

“We’ll use our combined experience of almost 300 years to do more of the things that matter to you.”

As confirmed last November, the new combined group will be led by David Thorburn as chairman, with Hughes as CEO and Lee Raybould as chief financial officer (CFO).

Nick Slape will retire from his role as CEO of the Co-op Bank and the group confirmed there would be a handover period in the coming weeks to ensure a smooth transition.

Until a permanent appointment is announced, Hughes will be interim chief executive of the Co-op Bank alongside his group role.

Hughes continued: “We’re still going to operate as the Co-op Bank and Coventry Building Society for the time being. This means there will be no change to the way you use our services right now.

“If you have accounts with both Coventry Building Society and the Co-op Bank, you’ll continue to benefit from the maximum protection offered by the Financial Services Compensation Scheme through each organisation.”

---