In the context of registered securities offerings, an existing stockholder of a company that is selling shares in a registered public offering. A public offering of shares by existing stockholders is known as a secondary offering. Existing stockholders can sell shares in a company's initial public offering or in a follow-on offering.

Existing stockholders who sell shares through initial purchasers in unregistered offerings exempt from registration under Rule 144A and Regulation S are also referred to as selling stockholders.

For more information on registered secondary offerings, see Registered Offerings After the IPO: Overview.