In an indication of the far-reaching nature of the restrictions, HSBC points out that under U.S. sanctions, an entity that is 50% owned or more, directly or indirectly, by one or more blocked persons is itself also considered blocked, whether or not it is on the sanctions list.
EU sanctions apply a similar rule, HSBC said.
Britain said on Monday it was taking further measures against Russia in concert with the U.S. and the EU, including banning any British entities from undertaking transactions with the Russian central bank, finance ministry and wealth fund.
The London Stock Exchange on Friday said it had suspended VTB unit VTB Capital's membership.