Russian billionaire Mikhail Prokhorov says he is stepping down as head of his Civic Platform political party.
Prokhorov said his sister, Irina Prokhorova, will replace him.
Prokhorov, who finished third in the Russian presidential election in 2012, said he was not quitting politics.
His sister said the party will focus on the upcoming Moscow city elections.
Prokhorov founded the Civic Platform in 2012.
A former owner of the Norilsk Nickel company, Prokhorov is the owner of the NBA's Brooklyn Nets.
Prokhorov was estimated by "Forbes" in 2012 to be Russia's seventh-richest man, worth $13.2 billion.
Based on reporting by Interfax and ITAR-TASS