The rules of trading are just these few lines: A sharp drop will always have a rebound, don’t sell; a slow drop will keep dropping, sell. A sharp rise will inevitably pull back, sell; a slow rise will keep rising, don’t sell. If there’s a big drop in the morning, don’t panic sell, it usually rebounds in the afternoon. If there’s a big surge near the close, reduce your position, as there’s a high chance of a pullback the next day.