As a general rule, section 83 requires a person (which is not necessarily a natural person) performing services to include in income the amount that the fair market value of the property received exceeds the amount paid for the property once the property is "substantially vested." That is, a person generally does not report income until the earlier of the time when the person can transfer his rights to the property or no longer has a substantial risk of forfeiting the property, unless the person makes a "Section 83(b) election."