Porsche is considering a return to F1 as an engine supplier since attending series boss meetings at the 2017 Italian Grand Prix.
It then renewed its interest last year when the worst effects of the emissions scandal were over.
According to a document released earlier this week by the Moroccan Conseil de la Concurrence – the national government that requires applications to be subject to mandatory publication once approved – Porsche is poised to buy 50% of Red Bull Technology.
This would pave the way for a powertrain partnership from 2026 and the partial investment in the race team, possibly the first sign of a contingency plan for Red Bull owner Dietrich Mateschitz.
It was widely suggested that the Porsche-Red Bull deal, expected to last 10 years, would be announced at the beverage company’s home race, the Austrian GP, earlier this month.
The Moroccan document, meanwhile, includes a date of August 4 on which the tape will be made public.
But team boss Horner thinks there is still a “long process” lurking, after an FIA-induced delay on the exact specification of the 2026 powertrain regulations.
Porsche and Audi’s involvement is believed to depend on dumping the MGU-H, a greater reliance on sustainable fuels, and a big enough reset to make them competitive.
Horner said: “There are some important caveats that we need to take first before things can get close to progress.
“That mainly focuses on what the final technical, sporting and financial rules for the power unit will be.
“Will they be fair and equitable to the new entrants versus the current incumbents?
“That is the first piece of the puzzle that needs to be completed.
Porsche GT Team logo
Photo by: Rainier Ehrhardt
“It’s something I know the FIA is working hard on. Hopefully we’ll get to see that in the coming weeks.
“At that point we can try to talk further with the guys from Porsche.
“It will be a fairly lengthy process, I assume.
“The most fundamental thing is, what are those rules for 2026 and are they attractive enough for an entity like a Porsche or an Audi to get into Formula 1?”
Horner stressed that Porsche had to fit into the ‘Red Bull philosophy’ and added that it would be “absolutely fundamental to any discussion not to change that”.
As part of the team’s “TBEN”, Red Bull is committed to a longer-term commitment from Porsche.
“We’re actually only in a discussion phase and there are so many regulatory caveats,” Horner said.
“Red Bull has shown its commitment to Formula 1, its longevity in the sport.
“Everything we look at is very much focused on the long term. We are not looking for a short-term solution.
“Strategically, it should of course fit in with Red Bull’s long-term plans for its commitment to Formula 1.”
He also assumed that the new Red Bull Powertrains site, with the ‘Rindt’ factory built in 55 weeks, will ‘start shortly’ its first engine.