The wholly-owned subsidiary is created out of the merger of two groups.

The paperwork has been completed: Deutsche Bank's private and commercial bank - or DB Privat- und Firmenkundenbank AG to give its full German name - is now live as a formal entity. The business has been created out of the largest merger of two banks since the European Central Bank began to supervise the system.

The organisation is a wholly-owned subsidiary of Deutsche Bank, assembled via the merger of Deutsche Bank Privat- und Geschäftskunden AG and Deutsche Postbank AG.

"Synergies from the new entity's formation will rise to at least €900 million ($1.042 billion) a year by 2022 at the latest," Christian Sewing, Deutsche's recently-installed chief executive, said. "To do this, a total of €1.9 billion will be spent on restructuring costs and other investments, mainly in IT. As a result, this business's cost/income ratio will narrow to under 65 per cent by 2022," the bank said.

This business entity serves serves more than 20 million private clients, around half of whom use the bank's online offering, as well as one million commercial and corporate clients. Assets under management, including sight deposits, are more than €331 billion, while it employs 28,000 staff.

The private and commercial clients business will continue to operate both brands – Deutsche Bank and Postbank – so clients will retain their established contacts.

Deutsche, Germany's largest bank and for years a lender associated with the backbone of the German economy, has been through torrid times. As well as boardroom changes, the bank has moved to slash costs, trimming its equities business, while it stresses it sees wealth management as an important growth area.

“The new DB Privat- und Firmenkundenbank shows our commitment to our home market,” said Frank Strauß, member of the management board of Deutsche Bank AG and head of private and commercial banking. “Starting from this position of strength as the undisputed leader in Germany’s banking market, we intend to drive the digital transformation of our business, continue to grow and consistently make a significant contribution to group earnings,” he said.

A stepping stone for the growth plan, Deutsche said, was how the European Central Bank has recently granted the capital waiver that enables the bank to manage liquidity better across DB Privat- und Firmenkundenbank and other Deutsche Bank businesses.