Fiat Chrysler's Marchionne being treated in Zurich's University Hospital

A Fiat Chrysler spokesman confirmed Marchionne was in Zurich’s University Hospital, one of the country’s largest medical centres.

The spokesman did not give the 66-year-old Italian-Canadian executive’s condition or say in which of the hospital’s 43 divisions he was being treated.

Fiat Chrysler named its Jeep division boss Mike Manley on Saturday to take over immediately from Marchionne, who had been due to step down next April.

SGS, the Swiss logistics services company, also announced on Sunday that it had named a new acting chairman to take over for Marchionne, since his illness prevented him from fulfilling the role’s obligations.

SGS said in a statement it was “deeply saddened” by the news, as did Lausanne, Switzerland-based Philip Morris International, where Marchionne is also on the board.

Marchionne was credited with rescuing Fiat and Chrysler from bankruptcy after taking the Italian carmaker’s wheel in 2004. On Saturday he was also replaced as chairman and CEO of Ferrari and chairman of tractor maker CNH Industrial - both spun off from FCA in recent years.

In additional management changes linked to Marchionne’s illness, Ferrari named FCA Chairman and Agnelli family scion John Elkann as new chairman, while board member Louis Camilleri becomes chief executive.