The Co-operative Bank has said its transformation programme is “materially complete” ahead of its merger with Coventry Building Society.
The bank's multi-year overhaul includes a £100 million IT cash injection.
Co-op also revealed in April a series of organisational changes across the bank, which will see around 400 roles axed.
In a first quarter trading update, the bank said that it had reached "significant milestones" as part of its transformation plans, with only seven per cent of total customers left to migrate onto its new system.
The update comes after it was announced last month that Coventry would acquire Co-op Bank as part of a £780 million deal.
Co-op first entered into exclusive talks with the building society late last year.
Coventry plans to integrate the bank gradually over several years, with the combined group expecting a balance sheet of £89 billion based on figures recorded at the end of last year.
"Significant progress has been made in our IT simplification programme, which is now nearing completion, with only six per cent of savings customers and 14 per cent of mortgage customers left to migrate," said Nick Slape, chief executive, the Co-operative Bank.
The chief exec went on to say that the bank's risk balance sheet "remains resilient", with all key financial performance in line with expectations and no change to full-year guidance.
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