Inexplicable crashes and freezes that disrupt markets and can cost millions of dollars in seconds mean that tighter policing of electronic trading is inevitable. While formal EU rules on the issue are not expected to come into force for another two years, Hong Kong has introduced a strict requirement that some market participants say could serve as a model for European regulation.

To limit the risk of market disruption caused by algorithmic trading, in January the Securities and Futures Commission in Hong Kong introduced a rule that everyone who designs or uses an algorithm must be "suitably qualified" - in other words, understand how it works.