Austria's OMV, BEH, Turkey's Botas, Romania's Transgaz, Hungary's MOL and Germany's RWE are partners in the Vienna-based Nabucco Gas Pipeline International, the project company of the 3,300 kilometre pipeline designed to connect the Caspian region and the Middle East with the Turkish and European gas markets.
The deal could be reached on January 10, when the shareholders will meet, Mihail Andonov told a press conference in Sofia.
RWE is currently in talks to sell its stake to OMV, which in turn could sell it to Shah Deniz II, he added.
Nabucco is expected to start gas deliveries by 2017.
The Shah Deniz gas field in Azerbaijan is estimated to contain 1.2 trillion cubic metres of gas.