By Alan Baldwin
LONDON (Reuters) - Former world champions Red Bull and Nissan's Infiniti premium car brand will end their Formula One partnership at the end of this year, the team said in a statement on Sunday.
Infiniti, part of the Renault-Nissan alliance, have been with Red Bull since 2011 and title sponsors since 2013.
The relationship had looked to be on borrowed time after the team fell out with Renault as a result of the poor performance of the V6 turbo hybrid power unit provided by the French manufacturer.
The car marque could now follow Renault, who announced last week that they were buying struggling Lotus and returning as a full works team.
Red Bull, who won four successive world drivers' and constructors' titles with Renault engines, tried and failed to secure an alternative engine for 2016 and have ended up with a compromise instead.
The team announced last week that their 2016 power unit would be still provided by Renault but branded with the name of new Swiss luxury watch partner Tag-Heuer.
"The team today announces that its commercial partnership with Infiniti will conclude at the end of 2015," Red Bull said in a statement.
"Red Bull and Renault have reached a mutual and amicable agreement that will see the French car manufacturer continue to supply the team with engines for the 2016 Formula One season, and this new agreement does not cover any marketing activity for the Renault-Nissan Alliance."
Media reports have suggested the Infiniti deal was worth some 40 million euros ($43.53 million) a year to Red Bull, and possibly more.Together, Red Bull and Infiniti won three drivers' and constructors' titles as well as 35 Grands Prix wins, 37 pole positions and 80 podiums.
"They became the title sponsor of the team in 2013 where Infiniti enjoyed greater visibility than any other manufacturer in the sport," said team principal Christian Horner.
(Reporting by Alan Baldwin, editing by Justin Palmer)