Note how the $TICK line quickly moved below zero during the morning session and largely stayed below zero for most the morning. This tells us that stocks were persistently trading with weakness (on downticks) throughout those morning hours. Something interesting happened midday, however. As we made new lows in SPY, we were seeing much less selling pressure. Indeed, the final low was preceded by a sizable spurt in buying. From that final low, we saw a significant spurt in buying and stayed above the zero line for most of the remainder of the day.