"RusAL announces that an agreement with the Onexim group to buy 25% plus one share in Norilsk Nickel has come into force," the company said in a news release.
The press service of Interros said on Friday that the financial holding, owned by metals tycoon Vladimir Potanin, would not buy a blocking stake in Norilsk Nickel from Onexim.
Onexim is an investment fund owned by Potanin's former partner, Mikhail Prokhorov.
Prokhorov earlier proposed selling a blocking stake in Norilsk Nickel to RusAl for $3 billion less than he had offered to his former business partner.
The tycoon's Onexim investment fund made a $15.7 billion offer to Vladimir Potanin in late November to buy out 25.1% of Prokhorov's stake in Norilsk Nickel. Prokhorov and Potanin are key shareholders with 28.2% and 25.3% in the metals conglomerate respectively.
However, the Vremya Novostei daily said, citing a source close to the deal, that 29% plus one share in Norilsk had been offered to RusAl for $14.7 billion. The offer includes two share packages - 25% plus one share for $12.7 billion, and about 4% of shares believed to be held by Prokhorov via the Invest company for over $2 billion.
In January, Potanin's holding company Interros said it would buy out Prokhorov's stake, and the two billionaires would remain joint owners of Interros's other assets, including major gold producer Polyus Gold.
Prokhorov resigned as general director and president of Norilsk Nickel in March. Talks over his stake have continued most of the year without result.
UC RusAl, controlled by Oleg Deripaska's Basic Element, became the world's largest aluminum producer after a March merger between RusAl, rival Sual and Swiss Glencore's alumina assets.
The market capitalization of Norilsk Nickel, which accounts for more than 20% of global nickel output, over 10% of cobalt and 3% of copper, and 96% of Russia's nickel production, has risen 40% since the start of the year, to about $40 billion.
