An International Securities Identification Number (ISIN) is a unique twelve-character alphanumeric code assigned globally to specific securities, including stocks, bonds, warrants, and derivatives, under ISO 6166 standards. The code consists of a two-letter country prefix indicating the issuer's domicile, a nine-character national security identifier, and a single check digit at the end. Financial institutions, clearing houses, and global stock exchanges utilize ISIN codes to ensure unambiguous identification and error-free settlement of cross-border trades.