Tupras is slated as the central element of the country's privatization program.
At the end of seven rounds of closed bidding TUPRAS Acquisition Cons. OGG-Petrol Ofisi OGG; ENI Refining and Market Division (Italy) and MOL (Hungary), were eliminated for submitting the lowest bid.
The remaining six bidders took part in an open auction.
OMV (Austria), Anadolu Joint Venture Group and Petrol Ofisi-TAC Joint Venture Group withdrew from the auction on the first round, and OYAK Group withdrew on the ninth round.
At the end of the ninth round of the open auction, the highest bid reached $4.06 billion.
A previous $1.3 billion attempt to sell the refinery failed last year due to an objection by labor unions.