The sanctions were bringing "some tensions" to the family's business and personal lives, admitted Mr Rotenberg, who was educated in London and, like his father and Mr Timchenko, holds Finnish citizenship.
The Langvik, he said, could no longer open an account with a major bank with US operations, while family members – even those who were not directly sanctioned – had decided to refrain from travelling to the US for the time being.
Even paying the gas bill for his residence in Europe had become complicated, Mr Rotenberg said. "Of course you can pay the bill but you need two hours time to change the account and find a bank that's not connected to the US."
David Johnson, a partner at Vinson & Elkins, a Washington law firm with a sanctions practice, noted the US sanctions stated that no US person could deal with an entity or property, either majority-owned or controlled by one of the sanctioned individuals. "The bottom line is no US person can transact business with this hotel," he said, adding that the same appeared to be true for Hartwall Arena, given the clear ownership.
US institutions will have a harder time determining whether they can continue to work with companies where ownership or control is less clear, Mr Johnson said.
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Bank Rossiya, a top-20 lender which was sanctioned, has significant Russian media holdings. Russian media companies, controlled by the bank and partners, do business with the top five international advertising agencies, which in turn work for some of the biggest US multinational brands.
Bank Rossiya, for instance, owns a stake in Vi, Russia's leading television media buyer, which works with leading international ad agencies including WPP, Omnicom and Publicis.
A spokesman for Vi, which controls one-third of Russia's TV advertising market, said Bank Rossiya had a 16 per cent stake in Vi and did not exercise control over the company. However, a person with direct knowledge of VI's workings said that Bank Rossiya effectively controlled the company through affiliated structures.
He added that big international ad agencies were likely to only terminate their relationship with Vi "at gunpoint". "Russia is a major advertising market and the only market that's growing" he said.
A senior executive at an American media agency that works with Vi agreed, saying his employer's compliance department had not even looked into the matter.
"Nobody in the industry here thinks that the sanctions will have any impact," he said. "As for us, we haven't received any instructions from headquarters on this."