People tend to like to buy round lots of 100 shares or multiple of 100s........Many small investors therefor are more prone to buy stocks below $100. Therefore at $38 it will be more attractive to more investors. At least that is the theory.
Normally the officers plan a long time in advance when their sells take place. It's not like they say "the stock just popped and I think I will sell some". We should have good earnings and a split in the wings which will put the stock price at a price more appealing for investors. FB has a bright future with Zuke most likely replacing Bill Gates as the richest man.