A Section 83(b) election is applicable when a substantial risk of forfeiture exists in the underlying shares of an equity grant. In privately held companies, an 83(b) election is made upon an exercise of stock options or a grant of stock ONLY if the shares you get must vest before they become yours to sell or transfer. In limited situations, stock subject to a company buyback or repurchase right is considered to have a substantial risk of forfeiture. Although the SEC imposes restrictions on resales of private company stock, they are not involved in this share-vesting requirement.
You do not need to file an 83(b) election for standard stock options that you can exercise only after vesting, as the stock received at exercise is not subject to a substantial risk of forfeiture.
Alert: Restricted securities, which are shares in a private company that are not registered with the SEC and are not easy to sell, represent a different type of restriction that does not require a Section 83(b) election at exercise.