Fat finger (rumor that apparently a large stop order in ZB went in as a limit one by mistake)... Everything above 131-12 busted (or, rather, adjusted to 131-12), allegedly. Similar in ultras.
Some guys in this forum may have been saying for years that one may hit the bid with any size, and a market would not move. If it falls, the fat finger is always there to explain it.
Fat finger (rumor that apparently a large stop order in ZB went in as a limit one by mistake)... Everything above 131-12 busted (or, rather, adjusted to 131-12), allegedly. Similar in ultras.