Golden rule is if you exercise sell enough immediately to pay off the tax burden. If you have a lockout get it written into your contract that you can sell them

Golden rule is if you exercise sell enough immediately to pay off the tax burden. If you have a lockout get it written into your contract that you can sell them to another private holder (e.g another employee, investor). It's legitimate for a private company to want a lockout, they don't want external influence in a company but most will allow internal if you get it in contract.