Russian billionaire Mikhail Prokhorov announced on Friday that his Onexim investment holding group had sold its 37.78-percent stake in the gold producer Polyus Gold for $3.6 billion (2.7 billion euros). The stake was acquired by an organisation controlled by Russia's lower house parliament member Zelimkhan Mutsoyev and by Gavriil Yushvayev, a former co-owner of the Wimm-Bill-Dann juice and drinks producer, Interfax reported. Polyus Gold, a London-listed firm, has the world's third-biggest reserves of the precious metal.