Adderton took to social media today to announce the impending end to all of the brand's "investments, sponsorships and commitments" relating to Supercars.
As it stands Boost Mobile is the naming rights backer of the Erebus Motorsport squad and the Gold Coast 500 event, as well as having a telco deal with Supercars itself.
It is also backing a third Erebus car for the Bathurst 1000 for Greg Murphy and Richie Stanaway.
"We will finish out the year of all our [Supercars] investments, sponsorships and commitments as per our agreements and then take a break from Supercars," Adderton wrote.
"I will not be commenting, [taking] calls or interviews related to anything related to the Supercars owners' directions.
"I wish the teams and the drivers well for the future. I want to thank the fans for being the best fans in any sport. Supercars [is] lucky to have you so let's have a blast and go out with a bang.
Adderton was part of an unsuccessful bid to purchase Supercars from Archer Capital last year, which was beaten by the RACE consortium.
Since then Adderton has been publicly critical of RACE at times, particularly recently as details of a foreign takeover bid came to light.
The first indication that he may pull his backing, or at least threaten to, came last night when he blasted Supercars chairman Barclay Nettlefold for appearing in a photo with driver Chaz Mostert at an Optus appearance.
"I have no issues with [Walkinshaw Andretti United] and Optus sponsorship but when RACE officials, who have an exclusive agreement with [Boost Mobile], so such disrespect... would they go and visit and photograph themselves in a [Supercheap Auto] store?" he wrote.
"This will cost you [Supercars]."
