ISIN

An ISIN, or International Securities Identification Number, is a 12-character alphanumeric code used to uniquely identify a security for trading, clearing, and settlement across borders. Defined by the ISO 6166 standard, an ISIN helps securities.Linked to cross-border workflows, ISINs enable unambiguous reference to financial instruments such as stocks, bonds, funds, and other securities.

The structure of an ISIN consists of three parts: a two-letter country code (ISO 3166-1 alpha-2) that identifies the issuer’s country, a nine-character national security identifier that uniquely identifies the instrument within that country, and a single check digit at the end that validates the code. The check digit is calculated using the Luhn algorithm, after converting any letters to their numeric equivalents. A typical example is US0378331005, where US is the country code, 037833100 is the national identifier, and 5 is the check digit. This ISIN corresponds to a security commonly linked to a CUSIP-based identifier.

Administration and use: ISINs are issued and maintained by national numbering agencies (NNAs) within each country, under coordination by the Association of National Numbering Agencies (ANNA). They are adopted by exchanges, clearinghouses, depositories, and regulators worldwide to support trade matching, settlement instructions, and regulatory reporting. While ISINs cover a wide range of securities—including equities, bonds, mutual funds, and exchange-traded products—not every instrument carries an ISIN in every market, and some jurisdictions use alternative identifiers as complements or substitutes (such as CUSIPs or SEDOLs).