The flash crash on May 6 lasted only minutes but the debate into its causes and preventative measures continues. Financial News’ US correspondent Shanny Basar rounds up some of the conclusions and opinions that reflect the mood of US regulators and market participants more than a month after the event.

• In about 20 minutes, starting at 14:40 EST, the Dow Jones Industrial Average dropped 998.5 points, or 9.2%, with some stocks and exchange-traded funds momentarily falling to almost zero before the index recovered to end the day 348.6 points down.