An overview of the so-called New York Stock Exchange (NYSE) 20% rule requiring stockholder approval before a listed company can issue 20% or more of its outstanding common stock or voting power. This Note examines how to apply the rule, make calculations under the rule, claim an exception under the rule and structure transactions to avoid or defer stockholder approval. This Note can be used by companies and practitioners before any issuance of common stock, other equity with voting rights or convertible securities and warrants.