The Briton has built the team up from its lowly position when it initially took over the Jaguar operation ahead of the 2005 season, with Red Bull now firmly a powerhouse in world motorsport.
But if the current investigation leaves him in an untenable position, who could take over his position?
Red Bull is said to have two main candidates...
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The obvious candidate with experience within Red Bull's ranks is Jonathan Wheatley.
He is currently the team's Sporting Director and seems a suitable choice to succeed Horner in any case. If the current situation dictates, it would be reasonable to suggest he would fill the void at least on an interim basis to cause the least amount of friction as possible on preparations for the upcoming season.
Wheatley was a prominent figure during Max Verstappen's first Drivers' title in 2021, where he was often the voice heard in exchanges with then-FIA Race Director Michael Masi.
But if reports are to be believed, Oliver Oakes could be the heir to Horner's position.
The leader at junior formula competitors Hitech GP, Oakes was a part of the Red Bull junior set-up during his own career and has kept the relationship going with a number of recent development drivers taking to the track behind the wheel of one of his cars.
The 36-year-old is familiar with Marko and vice versa, which reportedly sees Oakes as an ideal candidate to succeed Horner.
Oakes was the 2005 World Karting Champion and recently tried to get Hitech onto the F1 grid, though the application was rejected by the FIA.
It is worth pointing out that Red Bull's hierarchy would be open to installing a CEO alongside any prospective Team Principal, whilst it is clear that any succession plan is only necessary if the investigation falls against Horner.