People in positions like these divest for a large number of reasons, none of which can usually be determined by the public filings.  Most insider sales are done via 10b5-1 plans and are planned far in advance for the specific purpose of avoiding the appearance of insider trading:https:  Investopedia In the case of Evan Williams, because he just resigned from the board, all of his transactions for the next 90 days must be disclosed due to a different rule. I've done a fair bit of work in this area, and find that too many on these boards try to extrapolate more information from insider stock sales than is actually there.