[saimiam]

If it were a straight drop of 99% - say it is trading at $100 at tick_1 and at tick_2, it is trading at $1, trading will be halted at point which happens to be after a 99% drop. In reality, stocks gap downwards in a series of shallow steps which are unlikely to be 99% in one tick.

More info on the 10% trading halt rule: https://www.nasdaqtrader.com/Trader.aspx?id=TradeHalts