ETFs are closed end funds that trade during market hours like stocks. (noroboinvestor.com)
The second comparison is to the number of mini flash crashes during any three minute window during regular market hours (9:30 am — 4:00 pm) during the same days. (journals.plos.org)
Market Timing: As ETFs trade continuously during exchange opening hours there is a risk that ETF transactions are executed outside of the normal market hours of the underlying fund constituents. (uk.scalable.capital)