Audi’s planned Formula 1 entry for 2026 has reached an “important milestone” after it was announced it has bought a minority stake in Sauber.

Ahead of last year’s Belgian Grand Prix, Audi revealed it would be entering F1 with its own works team when the revised power unit regulations come into force in 2026.

The German manufacturer outlined its plan to forge a strategic partnership with Sauber that would see the its cars engineered and developed at Sauber’s Hinwil base in Switzerland, while Audi would build the power units at a separate factory in Germany.

While there were no details over whether Audi would proceed by purchasing a stake in Sauber, it was suggested by the team that it would happen in due course. 

But in a statement issued on Monday, Sauber confirmed Audi had gone ahead and bought a minor stake in the Swiss-based outfit.

“The Sauber Group is pleased to announce that, as per the plans outlined in October last year, Audi acquired a minority stake in the Sauber Group in January 2023,” the statements reads. 

“This is an important milestone on the way to Audi’s entry in Formula One, scheduled for 2026, for which the Sauber Group will be the German brand’s strategic partner.”

Sauber’s Hinwil facility will prove a crucial part of Audi’s F1 operation as it includes a state-of-the-art wind tunnel, which the team purchased in the early 2000s.

By the time Audi joins the F1 grid, Sauber will return to running under its own name as its partnership with Alfa Romeo will cease at the end of this season.