Niki Lauda has axed his sponsorship by the financially embattled company Money Service Group.
Sauber is also sponsored by the Liechtenstein based firm, who convinced Austrian legend Lauda to ditch his famous red cap in favour of a blue one for 2011.
But reports in recent days suggested MSG is in difficulties, with its founder and boss departing and suggestions the company has liquidated.
"I have tried to reach Mr Seidl but unfortunately I have not heard from him yet," Lauda said this week.
I have tried to reach Mr Seidl but unfortunately I have not heard from him yet
The Austrian Independent reported on Friday that the former triple world champion has now cancelled the deal and reverted to his familiar red cap colours.
Other media reports said Liechtenstein prosecutors are investigating Money Service Group for commercial fraud.
"I'm glad about wearing a red cap again," Lauda said on Friday, confirming he decided to cancel the sponsorship deal "due to the turbulences of the past few days".
62-year-old Lauda's new cap does not feature a sponsor logo.