Shares of Russian businessman Oleg Tinkov's credit card supplier TCS plummeted Friday after the U.S. Department of Justice charged its founder with fraud and demanded his extradition from Britain.
Shares of TCS (Tinkoff Credit Systems) group were showing a loss of more than 17%t on the London Stock Exchange and 24% on the Moscow Exchange at around 1510 GMT.
Tinkov stands accused of concealing $1 billion in assets and income from the U.S. tax authorities at the time when he renounced his U.S. citizenship in 2013, which required him to report his assets following a stock market flotation in London, the Department of Justice said Thursday.
"The indictment charges that Tinkov filed a false 2013 tax return" and he faces a possible six years in prison if convicted, it said.
A UK court issued a warrant for Tinkov's arrest in February, but he posted bail of some £20 million ($26 million) and is able to remain free in London abiding by restrictions, British and Russian media reported.
The next court hearing in the case initiated by US authorities is scheduled for April 27, Russia's state news agency TASS reported.
In a statement on Friday, Tinkov announced that he has been fighting leukaemia and had stepped back from day-to-day management of the business two years ago.
He said he has a legal team dealing with the "U.S. issues relating to my taxes from the past" and is focusing on his health.
Founded in 2006, Tinkoff bank has seen a meteoric rise. Today the lender has over 10 million customers.
Tinkov has a somewhat controversial image in Russia, clashing with critics on the internet and using vulgar language.
He is also a well-known figure in the world of professional cycling and owned a cycling team for several years.