Swiss bank UBS CEO Sergio Ermotti addresses a news conference in Zurich
Swiss bank UBS CEO Sergio Ermotti addresses a news conference in Zurich, Switzerland February 20, 2020. Reuters

UBS Group AG has rehired Sergio Ermotti as CEO to steer its massive takeover of neighbour Credit Suisse - a surprise move that seeks to take advantage of his experience in rebuilding the bank after the global financial crisis.

His immediate challenges will include laying off thousands of staff, cutting back Credit Suisse's investment bank and reassuring the world's wealthy that UBS remains the best place to park their cash.

Current CEO Ralph Hamers was a notable absentee from the announcement of UBS's takeover of Credit Suisse on March 19 - a deal backed by more than 200 billion francs ($217 billion) of state cash and guarantees engineered by the government, central bank and regulators.

The next day, Hamers looked bleary eyed as he described the end of Credit Suisse as a "sad day" that nobody wanted.

Ermotti, the current chairman of Swiss Re, will take the helm from April 5. He was chief executive of UBS from 2011 to 2020.

Hamers, who succeeded Ermotti in November 2020, "has agreed to step down to serve the interests of the new combination, the Swiss financial sector and the country," UBS said in a statement.

"The board took the decision in light of the new challenges and priorities facing UBS after the announcement of the acquisition," UBS added.

UBS ditched Hamers, who had no big-ticket M&A experience under his belt and faced the task of combining two banks with $1.6 trillion in assets, more than 120,000 staff and a complex balance sheet.

Ermotti said he was looking forward to integrating UBS and Credit Suisse.

"The task at hand is an urgent and challenging one," Ermotti said in a statement.

"In order to do it in a sustainable and successful way, and in the interest of all stakeholders involved, we need to thoughtfully and systematically assess all options."

A nearly 30-year veteran of Dutch lender ING, Hamers had been a surprise choice when he was appointed to lead UBS, as he had little experience in investment banking or wealth management.

At ING, Hamers was seen as a tech-savvy boss who spurned the image of a stuffy banker for a young, modern and approachable CEO, and there he was credited with overseeing a digital transformation.

The digital success at ING is what attracted UBS's then-chairman Axel Weber to poach him, at a time that some analysts said UBS's progress was stagnating.

($1 = 0.9209 Swiss francs)