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.
But Vremya Novostei said citing a source close to the deal that 29% plus one share in Norilsk was 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.
Both United Company RusAl and Onexim denied comments on the deal Monday, the paper said.
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.
Onexim earlier said the price for Potanin had been based on Norilsk average share prices in the past month plus a 12.5% premium. Potanin can accept the offer before December 21. But banking sector players said the businessman would hardly agree to the deal, the newspaper reported.
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.
In an interview earlier, Prokhorov said he did not consider his proposal to the former business partner to be tough or irrelevant to a market situation. "We set a timeframe for the division of assets together almost a year ago. This price was mentioned during our discussions and was not a surprise to him," he said.
