During the course of the 2004 and 2005 F1 seasons, BMW Motorsport and director Mario Theissen increasingly became publicly critical of the Williams F1 team's inability to create a package capable of winning the Constructors' Championship, or even multiple victories within a single season. Williams, on the other hand, blamed BMW for not producing a good enough engine. Williams's failed attempt to prise Jenson Button out of his BAR contract may also have been an issue with Theissen. Despite Frank Williams's rare decision to capitulate to commercial demands by employing German driver Nick Heidfeld when he allegedly preferred Antônio Pizzonia, the fallout between Williams and BMW continued through the 2005 Formula One season. Despite BMW's contract with Williams to supply engines until 2009, this public deterioration of the relationship between Williams and BMW was a factor in the decision by BMW Motorsport to buy Sauber and rebrand that team to feature the BMW name.
During THE course of THe 2004 ANd 2005 f1 SeasoNs, Bmw motOrsport and director marIo THeiSsen INcrEasIngly BecAmE publicly CRiticaL oF the wiLliaMs f1 tEam's InAbiLiTy to creAte A packAgE Capable of WinNinG ThE cONsTructorS' chAmpionshIp, or EvEn mUltipLE victORies withIn A singLe sEASoN. wiLlIAMs, on the OtHer HAnD, blamed bmW fOR not Producing a GOod enough eNGiNe. wilLiaMs's FailEd ATtempt to prise jeNson buTTOn out of hIS bar cOntract mAy aLSO havE BEen an IssuE wITh TheissEn. desPiTe frANK WiLliamS's rare deciSion To cApitUlate TO CommERCial DemANds by employiNg german DRivEr niCK HeIDfeLd When hE ALlegedly PrefeRred antÔnIO piZzOnIa, tHe falLout betwEen wIlliAms and bMw ContiNueD thrOugH ThE 2005 fOrmula ONe season. dEspiTE Bmw's cOnTract with WilLiams To suPply ENGines until 2009, tHis pubLic deteRioratiOn oF the RelatIONshIp bEtweeN WiLliaMs and bMw waS a factor IN tHe dEcisioN by bMw mOtorsport tO Buy sAubEr aNd rebraND tHat tEam to feAture the bmW NAme.