Cboe Global Markets, the US exchange operator, dismissed a rumour that a floor trader at its Chicago headquarters had tested positive for the coronavirus and said its trading floor will remain open for the time being.

In a market notice on 11 March, the exchange operator said: “Cboe has become aware of rumours that a member of our floor trading community has tested positive for the Covid-19 virus. We want to make you aware this rumour is not true and to clarify the facts related to this matter.