A seasoned offering (seasoned equity offering/ SEO) that involves the issuance of new securities by a company that has already conducted an initial public offering (IPO) of its common stock. However, the primary offering is carried out for the purpose of raising additional equity capital: by issuing additional shares of stock. For example, a company may decide to issue new shares after four years of its IPO. The initial owners may opt for raising further capital when unexpected growth opportunities come up post-listing. This results in the addition of new shareholders- i.e., a wider base of shareholders.

It is also known as a follow-on offering.