Russia Yevtushenkov arrest prompts Sistema share dive
Russian billionaire Vladimir Yevtushenkov has been placed under house arrest on suspicion of money-laundering, prompting shares in his company Sistema to plunge.
The Moscow Exchange temporarily restricted trading in Sistema as shares in the oil and telecom group fell 37%.
The head of a top business group has questioned the reason behind the arrest of Mr Yevtushenkov, 65.
But President Vladimir Putin's spokesman denied any political motive.
Mr Yevtushenkov has an estimated fortune of $4.4bn (£2.6bn; 3.4bn euros), according to Forbes.
His AFK Sistema group owns Russia's biggest mobile operator MTS as well as oil firm Bashneft. Bashneft shares also fell by more than 20% on Wednesday and trading was temporarily restricted.
Russia's Federal Investigative Committee said he had been accused of money laundering that involved the illegal acquisition of oil assets in the BashTek group in the Russian republic of Bashkortostan. In 2009, Sistema bought six BashTek companies, which were then taken over by Bashneft.
If found guilty he could face up to 10 years in jail, reports say. Sistema said in a statement that the acquisition of BashTek was "legal and transparent".
The arrest was immediately compared by Alexander Shokhin, head of Russia's Union of Industrialists and Entrepreneurs, with the detention of another billionaire, Mikhail Khodorkovsky, in 2003.
The former owner of oil giant Yukos spent 10 years in jail before being pardoned and leaving Russia last December.
"Without doubt this looks very like Yukos 2.0, because the charges apply to the head of a company that paid $2.5bn for assets and is now accused of stealing shares and money-laundering," Mr Shokhin told Ria Novosti.
Yukos was at one point Russia's biggest oil company but its assets were eventually broken up, many of them bought by Rosneft, now the world's largest oil producer.
Rosneft was earlier this year reported to be keen to buy Bashneft.
The state-run oil and gas company is controlled by Igor Sechin, who for years has been a close ally of President Putin. Mr Sechin has been targeted by US sanctions in response to the crisis in Ukraine.
Mr Khodorkovsky, in an interview with Russian business daily Vedomosti, said the Sistema chairman's arrest involved "purely commercial interests" rather than political motives. It also showed that President Putin had lost control and was not aware of what was happening, he said.
Mr Putin's spokesman, Dmitry Peskov said it was "absolutely untrue and absurd to try to paint this story with any political colours", Ria Novosti reported.