Some in the City have suggested the high risk strategy could have consequences for the banks' operations in the US - a crucial market for their Asian clients.
Aviva is believed to be the first major City investor to criticise the two giant banks' actions over China's renewed aggression over Hong Kong.
Former Conservative leader Sir Iain Duncan Smith said last week it was a "grave error" on HSBC's part and said he would close his accounts with the bank if he were a customer, but most in the City had seemed to be quietly supportive of the realpolitik that, in Hong Kong and China, companies simply have to do what Beijing wants.
Johnson has offered Hong Kongers UK citizenship if China imposes a national security law on the supposedly autonomous region.
The US, UK, Australia and Canada issued a rare joint statement opposing Beijing's move, while other countries, from Japan to Taiwan, have voiced their condemnation.
