[This is a backlog for a previous trading transaction. It may not fully represent my thinking at the time of the trading.]
I covered my short position in QQQ today with a loss of 9%. It seems my short is untimely. I recently read a book teaching disciplines in investing. That book recommends to close positions when a loss of more than 8% occur. I decided to follow this rule today. I'll not try shorting again in the near future. Especially, I feel people do not have much control when shorting an index. Maybe it's because Mr Market has its own timing.