As far as the SEC document from a private company:
Under Section 12(g) of the Exchange Act, a private company with total assets in excess of $10 million and 500 or more record holders of a class of equity security, each measured at the end of its fiscal year, must register the class of equity security with the Securities and Exchange Commission, unless it has an exemption from such registration. Stock options are considered to be a separate class of equity security under the Exchange Act. Accordingly, a company with 500 or more option holders (including holders of unvested options) and more than $10 million in assets is required to register its stock options under the Exchange Act, absent an exemption.
