Thank you Eoin. I appreciate the detailed response, both in the copy and in the audios.

In a situation like that, when trading in the ETFs was stopped many times during the hour-long downward spike and whiplash, would it have worked to have buy orders in the market for the ETFs at very low prices?  Or would the breakdown in the market mechanisms have meant, that these orders would never have been fulfilled?  I am thinking of that as a possible long-term strategy to benefit from similar occurrences. After all, unlike options it costs nothing, and if one puts the orders on CFDs instead of on the ETFs themselves, you don't have to store away cash in case of possible executions.

Eoin Treacy's view

Thank you for highlighting this important consideration. During a panicky environment it is debatable whether buy orders would be executed and I think it would depend entirely on the individual traits of asset classes and regulatory frameworks.  As you point out CFDs may be a more attractive proposition.

I saw headlines last week that Nassim Taleb’s fund did very well. His black swan options strategy is designed to profit from exactly the situation we were presented with a week ago. Against a background where “group think” among computer programs is a risk, this is the type of strategy which could act as an effective hedge.