$HQ so as many know, QTUM ETF owns 6,565,887 HQ shares (by far the majority of float). The QTUM ETF reviews weightings semi-annually per ETF documentation. This would mean next weighting change is not until December Surprisingly, they published a file Friday night that included changed ETF weightings, against the ETF's rules. This would mean ~3M HQ shares would have needed to be sold by Friday. As a result, index arbs on Monday knocked the stock down 32% on 3X average volume. Selling was massive from open to close Through a few conversations, the index provider corrected the error. Announcement just came out from index provider - Weightings will NOT be changed, other than extremely minor (pro rata) to allow QNT to enter the index ~3M HQ shares will not be sold now by the index. All the index arbs who sold the stock off 32% yesterday will need to decide on what to do Or they can pay 101% overnight rate