UBS has brought back its former chief executive Sergio Ermotti to lead the firm, following the takeover of Credit Suisse by the Swiss lender.

Ermotti will begin the job on 5 April, replacing Ralph Hamers, who succeeded Ermotti in 2020 when he stepped down after nine years in the role.

Hamers will remain at UBS and work alongside Ermotti as an adviser, the firm said.

The Swiss bank said in a statement that the move had been made "in light of the new challenges and priorities facing UBS after the announcement of the acquisition" and pointed to how Ermotti had transformed UBS during his time in the top job.

"This unique experience, together with his deep understanding of the financial services industry in Switzerland and globally, make Sergio Ermotti ideally placed to pursue the integration of Credit Suisse," UBS said.

In a statement, Hamers said he was "stepping aside in the interests of the new combined entity and its stakeholders, including Switzerland and its financial sector".

"Integrating Credit Suisse is UBS's single most important task and I am confident that Sergio will successfully guide the bank through this next phase. I am of course sorry to leave UBS, but circumstances have changed in ways that none of us expected," Hamers added.

Since leaving UBS, Ermotti has chaired Swiss Re. UBS said he will remain in the role of chair until shortly after the firm's annual general meeting on 12 April.

UBS chair Colm Kelleher added: "While the acquisition will support UBS's existing strategy, it imposes new priorities on us. With his unique experience, I am very confident that Sergio will deliver the successful integration that is so essential for both banks' clients, employees and investors, and for Switzerland. I know Sergio will hit the ground running."