Earlier quoted context omitted.
Are employees even able to sell on IPO day?
In a traditional IPO, there is generally a 90-180 day lockup period for existing shareholders (to prevent shares from flooding the market on day 1). This is one of the big benefits of a direct listing (see Spotify/Slack)...any shareholder can sell stock on day one.
These are common, but I don't think they apply to all share classes, so the big boys are free to get their money out.