Most likely, it involves private internal trading between employees. Those that would rather just take the cash and run can sell their stock to others who would like to invest more into the company.
Exactly how do they plan to let employees sell stock without accidentally becoming a public company?
they sell it to banks and/or investment firms who are basically buying a futures contract on a facebook ipo. the employee loses their rights to sell these shares, the bank gains the rights.
Exactly how do they plan to let employees sell stock without accidentally becoming a public company?
Is this stock being sold back to the company itself?