I believe most companies do not allow this.
Re:Uber opens at $42 per share
by JumpCrisscross on Friday May 10, 2019 @04:28PM
(#19881922)
> most companies do not allow this
As someone who does work in the space, no, most companies permit transfers. There are mechanisms in place to reasonably limit them, e.g. rights of first refusal and transfer fees. But Uber was unique in the degree to which they restricted transfers.
Uber was also somewhat unique among unicorns in uniformly blocking its employees from selling shares on the secondary markets.