Private company stock options are call options, giving the holder the right to purchase shares of the company’s stock at a specified price. This right to purchase -- or “exercise” -- stock options is often subject to a vesting schedule that defines when the options can be exercised. If you work for a privately held company and are offered stock options as part of your compensation package, it can be easy to overlook the potential upside that these investment vehicles may offer. However, just because your company does not trade on a major stock exchange does not mean you should scoff at the opportunity to acquire shares in the business. Private company stock is a type of stock offered exclusively by a private company to its employees and investors. Unlike public stocks, the purchase and sale of private stocks must be approved of by the company that issued them.