Audi announced in August last year that it will be entering F1 in works capacity on the advent of new engine regulations in 2026, amid a boom in the sport’s popularity across the world.

This was followed by the news in October that Sauber, which currently operates as Alfa Romeo Racing, will become its “strategic partner”, and use its Hinwil facility to build the chassis.

At that time, Sauber revealed that Audi will purchase a stake in the team at some point, but no further details had been forthcoming on this front since then.

Now, Sauber has confirmed that the German manufacturer has gone ahead and bought an unspecified stake in the Swiss-based team, as per the plans previously outlined.

Sauber described it as an “important milestone” for Audi’s much-anticipated debut in F1.

"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," it said in a statement.

"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."

Valtteri Bottas at Abu Dhabi testing 2022

While Sauber’s Hinwil facility, which included a state-of-the-art wind tunnel, will serve as an important base for Audi’s F1 programme, the German marque is currently building a separate factory at Neuberg in Germany to develop the power unit.

The 3,000-square-metre building will house test benches for the hybrid engine and is an expansion of the site that was previously the home of Audi’s wildly-successful LMP1 programme in the FIA World Endurance Championship.

The extension of the site is expected to be completed by the first quarter of 2024.

By that year, Sauber will operate in F1 under its own name, with its agreement with Alfa Romeo coming to an end after the end of the forthcoming season.

It will continue to use Ferrari engines until 2025, before morphing into the works Audi F1 squad the following year.