One, July 21, 2005 is an important day of the RMB exchange rate reform, the history of a significant portion of the stock's historical low (shares need to be reweighted) have appeared on this day.
Two, next Wednesday, July 22, China Construction new shares subscription.
Time and news are intertwined near the point of time, the recent market rose quite a lot, borrowing this one time to make adjustments is not surprising at all.