The man rumoured to be the new boss of Ferrari is Louis Camilleri, the former CEO of Philip Morris International who is now the chairman of the cigarette company which owns Marlboro and is Ferrari's primary sponsor, although the branding no longer appears on the cars.
Marchionne is the man in favour of promoting Sauber rookie Charles Leclerc to the Scuderia in 2019.
Marchionne took over as president of Ferrari in 2014 from Luca Di Montezemolo, who served more than 20 years in the role.
The La Stampa daily, the hometown newspaper of Fiat's headquarters city, Turin, where the boards were summoned to separate meetings, said the huddles were called to discuss who would succeed Marchionne.
Saudi Arabia rejects ratification of 'National Israeli Law'
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In a statement issued on Saturday evening, the Maranello-based company said: "The Board of Directors of Ferrari learned with deep sadness during its meeting today that Chairman and CEO Sergio Marchionne will be unable to return to work". In the meantime, Mike Manley named acting CEO.
Kent-born Manley joined DaimlerChrysler in 2000, taking over as boss of Jeep in 2009. He announced a major investment thrust to make more electrified cars even though he said traditional engines will continue to dominate production.
The FCA Group recently unveiled its five-year business plan running until 2022, focusing on the Alfa Romeo, Maserati, Jeep and Ram brands.
Marchionne is passionate about the Ferrari racing team, and even after his planned retirement from Fiat Chrysler he had said he wanted to stay at the helm of the sports auto company with the iconic horse symbol for a few more years. Those brands were expected to account for 80 percent of revenues by 2022, compared to 65 percent now.
Marchionne's tenure also has been controversial at times. "His worldwide experience in growing that brand will play a key role as he applies those techniques to all of the Fiat Chrysler divisions". The next corporate results are to be released on July 25.