The most plausible explanation, however, is that traders were gaming the system. The Hong Kong exchange is not alone in running a 10-minute auction every afternoon to settle outstanding trades: almost every other major market does this too, to calculate a price that will satisfy as many orders as possible. But unlike others, Hong Kong has no system of random closing: the auction ends every day at 4:08. That means that market participants have an incentive to time their bids. In this case, the downswing in HSBC caused by an order seconds before the deadline knocked about 212 points off the HSI. An issuer of index options callable that day might have been willing to wear a big loss on the shares.
不过，最有可能的解释，是交易员在利用系统进行赌博。香港证交所每天下午进行10分钟的收市竞价交易，以结清尚未交易的买卖盘。香港证交所并非唯一采取这种机制的证交所，几乎每一个主要市场都有这种机制，即计算出一个价格，以满足尽可能多的买卖指令。但与其它交易所不同的是，香港没有随机收市的机制：竞价交易在每日16:08时结束。这意味着，市场参与者有择时提交竞价的动机。此次，在截止期限之前几秒钟提交的一个卖出指令，导致汇丰股价暴跌，使恒生指数瞬间跌落212点。可在当天行使的指数买入期权的发行者，也许愿意承担股价大跌的损失。