MOSCOW, May 13 (RIA Novosti) - Russian tycoon Mikhail Prokhorov will sell a 50% stake in KM Invest to financial holding Interros, owned by his former business partner Vladimir Potanin, business daily Vedomosti reported on Tuesday.

KM Invest manages the joint assets of Prokhorov's investment vehicle Onexim and Potanin's Interros. Both billionaires, who had been involved in months of wrangling over how to divide their assets, reached an agreement on dividing KM-Invest in mid-April.

"The 18-month debacle over Potanin and Prokhorov dividing the assets of KM Invest is coming to an end. Yesterday, Onexim and Interros representatives confirmed that Prokhorov's investment vehicle will sell a 50% stake in KM Invest to Potanin by May 15," Vedomosti said.

KM Invest holds and manages assets worth about $14 billion, including 8% in metals giant Norilsk Nickel, 7.6% in the Polyus gold mining company, 57.8% in Open Investments, 91.1% in Soglasiye insurance company, 100% in diversified media company Prof Media, 25.8% in crude producer Rusia Petroleum, and about 38% in Rosbank.

Under the deal, Prokhorov will buy 27.5% of shares in Open Investments, 91% of shares in Soglasiye insurance company and 100% of shares in Rosbank managing company from KM Invest, the paper said.

The parties have not disclosed the sums involved in the deals. However, an Onexim representative said Prokhorov will pay tax of $700 million for the sale of shares in KM Invest. Prokhorov directly owns KM Invest's stock and will have to pay 13% income tax, the paper said.

In late April, Prokhorov closed a deal to sell his blocking interest of 25% plus one share in Norilsk Nickel to Russia's United Company RusAl, the world's largest aluminum producer. The deal was pushed through after Potanin refused last year to buy Prokhorov's blocking interest in Norilsk Nickel.