As the title states. However the AI can buy the stock that is owned by other AIs, and this sometimes frees shares that i then can pick up.
As a result, for me to kick an AI out of the game i have to do a complete buyout of a his stock in one go; while the AIs can cooperate to buy me out. 
(Probably) not a bug, but it bugs me that even companies that i wholly own i can not manage. 
