Russian Billionaire Tinkov Fighting Leukemia Amid IRS Claims

Russian billionaire Oleg Tinkov announced Friday he has been receiving treatment for acute leukemia since last October as he faces possible extradition to the U.S. on tax fraud charges.

Tinkov, 52, announced his health problems less than a day after the U.S. unsealed a tax-evasion indictment that claims he concealed $1 billion in assets and income when he renounced his American citizenship in 2013. He faces as much as six years in prison if convicted.

Shares in TCS Group, the London-listed parent of Tinkoff Bank, fell 30% on Friday, the biggest drop since 2015. Shares were at their session low ...