Sergio Marchionne has admitted that Ferrari are at risk of losing their champion drivers after 2017.

However, the great marque's president played down rumours that Sebastian Vettel is a real contender to replace Nico Rosberg at Mercedes next year.

"Both drivers are under contract for 2017," he said at Ferrari's world finals event in Daytona.

"What happens next, I don't know, but I think a lot depends on how we manage the 2017 season,

"If we repeat 2016, I do not think we will have the ability to attract excellent drivers."

As for new world champion Rosberg's seismic decision to leave Mercedes, Marchionne commented: "I was surprised, but I do not expect Mercedes to be weaker without him.

"Rather, I hope Ferrari will be stronger."

Vettel and Kimi Raikkonen ended 2016 in fourth and sixth place respectively in the standings.