You have to keep in mind that when everyone wants to buy a stock (or sell a stock), it’s the market makers job to provide liquidity and take the other side of the trade. That’s why so often we see stocks gap higher or lower from the previous close, only to “fill the gap” and return to that prior day’s close. As an example, check out Citrix Systems (CTXS). After reporting better than expected earnings results, CTXS gapped substantially higher and opened at 86.50. Its intraday high was 90.00 before hitting a low of 80.38 just six trading sessions later.