Russian investment bank Renaissance Capital has given up its much vaunted independence after selling a 50% stake to billionaire client Mikhail Prokhorov for $500m (€342m) amid the worst market falls in Moscow since the 1998 financial crisis.

Renaissance and the Onexim investment vehicle owned by Prokhorov, who made his money from metals and banking, will buy new equity amounting to 50% of the brokerage for $500m, with the old shareholders retaining a one-share voting majority.