Audi's Formula 1 boss has warned that the first couple of campaigns tackled by the Volkswagen-owned carmaker will be "tough".
Swiss-based Sauber, set to compete with the Alfa Romeo name for the last time this year, has a new title sponsor (Stake) and Group CEO in the form of Andreas Seidl for 2023.
Alessandro Alunni Bravi will be the 'team representative' at grands prix this season, and the Hinwil-based company has now confirmed the first phase of Audi's acquisition of the team.
Sauber said Audi has "acquired a minority stake", which Auto Motor und Sport speculates is an initial 25 percent ahead of an eventual 75pc takeover by 2026.
Current team owner Finn Rausing is expected to hang onto the final 25pc.
Until 2026, customer Ferrari engines will continue to power the cars, but the closer collaboration with Maranello looks set to ease down as Sauber gets closer to racing as Audi.
Audi intends to build its own engine in Neuburg an der Donau in Bavaria, with the program already headed up by former FIA safety director Adam Baker.
Audi reports that Baker, an Australian-born German, is developing "the technical, strategic, operational and financial concept" for the carmaker's 2026 foray.
"We have to be realistic," Audi Formula Racing CEO Baker told Deutsche Presse-Agentur. "The first and second year will probably be tough."