These are the big players, who outbid the small guys. Retail investors have a big stake in managing the price. In fact, if you observe carefully, the stock price always drops, even AFTER the company declares good results, ideally, the stock should rise if results are good, but it drops. This only means that the big investors have factored this is before the quarterly results and then dump large volumes, bring down the price and then gradually ramp it up. Anybody can observe this trend.