Sauber have become the latest Formula One team to sign up to plans to form a breakaway championship in 2008.
At a presentation last week by manufacturers to nine Formula One teams, five teams including Williams, BAR, Renault, Toyota and Minardi put their signatures on the Memorandum of Understanding.
McLaren have also indicated they could leave Formula One if it is the right thing to do.
The Memorandum is based on a document titled `Governing Principles for Grand Prix Motor Racing' which was previously agreed by the five manufacturers backing the idea, and forms several principles on what the manufacturers want a championship to adhere to.
Three teams left last week's meeting - Jordan, Sauber and Red Bull Racing - without signing up to the Memorandum, but now Sauber have decided to join in with the plans.
A Sauber spokesman told www.autosport.com: "It's true. We have signed up with the Memorandum of Understanding."
Talks of forming a new championship when the current Concorde Agreement, which governs Formula One, runs out at the end of 2007 have been widely mooted, with Ferrari so far being the only team to sign up to the agreement until 2012.
The support of the teams for a breakaway series means no guarantee of it actually happening in 2008, but just last week McLaren boss Ron Dennis spoke of wanting to have the choice to pull his team out of Formula One in the future, if it was the right way to go.