I don't know why people keep calling out the CEO stock sales, unless we find out something new this was almost guaranteed to have been done pursuant to a publicly filed 10b5-1 plan which has a 30 or 90 day cooling off period and must be filed when they have no material non-public information. So if the CEO could see this coming, anyone else could have too on the basis of the same information.

These things can come at you fast. They probably put in the trade instructions sometime last year and they are not permitted to make modifications to the 10b5-1 when they do come into material non-public information as that is itself insider trading.

Trading (or changing a 10b5-1 plan) while in possession of material non-public information, whether in your favor or not, is insider trading.