Swiss banking giant UBS announced on Tuesday that Credit Suisse chief executive Ulrich Koerner will join its executive board following the takeover of its fallen domestic rival.

Koerner will be the only executive from Credit Suisse to remain on board after the bank is absorbed by UBS.

The Swiss government strongarmed UBS into buying its rival for $3.25 billion after the collapse of three US lenders in March raised concerns about Credit Suisse's own financial health following a series of scandals in recent years.

Swiss-German Koerner, 60, held top positions at UBS for a decade before jumping ship to Credit Suisse last year with the tough task of reviving the troubled bank, where he had previously worked.

"With his knowledge of both organisations, he will be responsible for ensuring Credit Suisse's operational continuity and client focus, while supporting the integration process," UBS said.

UBS said it expects the merger to be completed "in the next few weeks".

The two banks will continue to operate independently "for the foreseeable future and UBS will carry out the integration in a phased approach", it said.

The combined bank will operate with five business divisions, each represented by executive board members.

UBS CEO Sergio Ermotti, who was brought back to Switzerland's biggest bank last year to handle the merger, said that the "integration of the businesses and legal entities will take time".

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