A hypothetical trader placed, after closing, placed a "market" order to purchase a small number of shares of a certain ETF. This particular ETF typically sees hundreds of trades per day.
Price at previous market close was say around 113.50. Hypothetical Trader's market order was executed at 114.98 at market open (setting a new 52-week high). The next trade, seven minutes later, was "back" at 113.53 (and the market proceeded from there, trading in a narrow band of a couple of cents in either direction for the next several days, as usual).
OK, so Hypothetical Trader clearly should not have entered an order after closing for market price. But:
Does not the exchange, or anyone else, place any sort of upper limit control on this sort of transaction? What if the counter-party for this trade had entered an ask of not 114.98 but rather 500.00?
Since this was clearly an anomalous trade, data for the trade seems to have been subsequently removed from most or all data reporting services--such that 114.98 no longer shows up as the 52-week high anywhere (either on the exchange site, the issuer's site, or the usual financial websites). It took around 24 hours or so for this value to be removed as the 52-week high. Who, and at what point, and under what authority, unilaterally (and arbitrarily?) decides that the price at which a certain trade was executed is going to be removed / not reported publicly?