Audi has purchased a stake in the Sauber Formula 1 team, ahead of its plan to compete in the sport from 2026 as both a constructor and power unit supplier.

The purchase was announced on Monday by Sauber, which described the deal as a minority stake. Audi could gradually increase the stake in the lead-up to its 2026 entry in an effort to gain more control of the team.

Sauber currently competes in F1 as Alfa Romeo but the automaker last August announced the arrangement would end after the 2023 season. Alfa Romeo hasn't said whether it is quitting F1 altogether, though.

Audi first announced plans to enter F1 last August and confirmed Sauber as its factory team two months later, after F1 finalized new sustainability measures starting from 2026. Sauber will be responsible for the development and production of the team's F1 car, at its base in Hinwil, Switzerland. Sauber will also be responsible for planning and executing the race operations. Audi will be responsible for the power unit. Sauber currently relies on Ferrari power units.

Fellow Volkswagen Group brand Porsche is also keen to enter F1 with its own power unit and possibly a factory team. Porsche was in negotiations with Red Bull Racing, though the talks ended last September without a deal being brokered. Porsche has said that it remains open to an F1 entry should the right opportunity arise.

Cadillac also announced in January that it will attempt to form an F1 entry with Andretti Global, the parent company of Andretti Autosport. However, details about the entry, including timing, haven't been announced, apart from the proposed team being based in the U.S. and having a support facility in the U.K.

Meanwhile, there are rumors that even Ford may be interested in becoming a partner of leading F1 team Red Bull Racing, as the sport continues to gain popularity in the U.S.