HSBC (née Hongkong and Shanghai Banking Corp) was considering moving its headquarters out of London and back to its roots in Hong Kong. Much of the consideration, and much of its decision not to move, were driven by Great Britain’s decision to tax all British banks’ overseas earnings in the aftermath of the Panic of 2008 and Great Britain’s subsequent decision not to tax HSBC so heavily.

However, I think the primary motivation for HSBC’s decision to stay put is buried at the bottom of the linked article.

…concerns about China’s growing influence over Hong Kong had helped make it more likely the bank would stick to London.

Indeed. Other banks should take heed.