British authorities are yet to renew Chelsea chairman Roman Abramovich's visa after it expired last month, two sources familiar with the matter told Reuters.
The billionaire, who has bankrolled the newly-crowned FA Cup winners since 2003, is in the process of renewing his visa as part of a standard procedure, one of the sources said.
It is taking longer than usual but there is no indication that the visa will not be renewed as there is no refusal or negative feedback, he added.
Millhouse, the company that manages Abramovich's assets, declined to comment. Britain's Home Office could not be reached for comment.
Abramovich, who is also a co-owner of London-listed steel producer Evraz, did not attend Saturday's FA Cup final in London as his club beat Manchester United.
He was also absent from a hearing at the London High Court this week at which Russian tycoon Oleg Deripaska was challenging the sale of a stake in mining giant Norilsk Nickel by Abramovich to Russian billionaire Vladimir Potanin.
David Davidovich, a top manager at Millhouse, told the London court that the Chelsea owner was in Switzerland, a transcript of the hearing showed.
Abramovich is Russia's 11th richest man with wealth of $US10.8 billion, according to estimates by Forbes magazine.
He made his fortune in the oil industry in the 1990s in Russia and after buying Chelsea in 2003, he has helped to transform the club into one of the most successful in Europe
Wealthy Russians have long favoured London as a place in which to live or do business.
However, relations between Britain and Russia hit a low after London accused Moscow of poisoning former double-agent Sergei Skripal in Britain in March.
Russia has denied any involvement in the poisoning and retaliated in kind.