Red Bull team principal Christian Horner has admitted that the team could join forces with Porsche in Formula 1 in the future.
Horner said Red Bull had “healthy dialogue” with Porsche but there were “some major caveats we need to get past before things get near progression”.
These focus on the finalisation of 2026 engine regulations, which are overdue.
Legal documents have been filed with authorities saying Porsche could take upon to a 50% shareholding in Red Bull.
But Horner said there was no formal agreement on any level at this stage.
The chief executive of the VW Group, which owns Porsche, said in May that both it and Audi had decided to enter F1.
Porsche has long been expected to join forces with Red Bull as an engine partner, while Audi is expected to buy a team. Swiss-based Sauber, currently racing as Alfa Romeo, are the favourites.
However, both are waiting for the 2026 engine rules to be finalised, something that has been delayed a number of times as stakeholders wrangle over the detail of the regulations.
The fundamental architecture of the power-unit is agreed – it will continue to be a 1.6-litre V6 turbo hybrid but with a different energy-recovery system providing a greater proportion of the total power output of the engine.
F1 is also committed to introducing fully sustainable synthetic fuels that are carbon-neutral in their life cycle – they emit only the amount of carbon that has been taken out of the atmosphere to make them.
The hybrid system is being simplified via the removal of the complicated MGU-H, the hybrid component that recovers energy from the turbo.
However, the final details of the rules are yet to be agreed, including to what degree new manufacturers will be assisted to get up to speed, and the financial limits surrounding design and operation.
Horner said: “At that point, we can sit down and have a further discussion with the guys at Porsche and it’s going to be a reasonably lengthy progress.
“But the most fundamental thing is what are the regs for 2026 and are they attractive enough for a Porsche or an Audi to come into F1?”
Porsche is expected to join forces with the new Red Bull Powertrains operation which has been set up to design a new engine for the 2026 rules. Porsche will provide technical expertise and significant budget.
The partnership is not believed to be the beginning of an exit strategy from F1 for Red Bull, who are committed to the sport for at least the remainder of this decade.