On the opportunity cost of nontradable stock options

Firms grant to their employees non-tradable stock options as an incentive device. Is the opportunity cost of issuing these options equal to the amount the company would receive if it sold the same options to outside investors? No, it is not, since the options granted to employees are non tradable, due to the incentive scheme to which they are related, and their value, i.e. the opportunity cost, may be lower or larger than the value of the corresponding tradable option.