ISINs

ISIN stands for International Securities Identification Number. It is a 12-character alphanumeric code that uniquely identifies a specific security or instrument for clearing and settlement across markets.

Structure and decoding: The first two characters are the ISO 3166-1 alpha-2 country code indicating the issue’s country of origin. The next nine characters constitute the National Securities Identification Number (NSIN), which may be numeric or alphanumeric and is assigned by the issuer’s national numbering agency. The final character is a check digit calculated using the Luhn algorithm.

Purpose and scope: ISINs cover a wide range of securities, including equities, bonds, debt instruments, money market instruments, and derivatives. They are used for post-trade processing and regulatory reporting, and are not the same as ticker symbols or prices. They provide a stable identifier that facilitates cross-border trading and settlement.

Issuance and governance: ISINs are defined under ISO 6166 and issued by national numbering agencies around the world. Each security issue receives one ISIN; a single issuer may have multiple ISINs for different issues or series. The same ISIN generally applies across markets and exchanges for the same instrument.

Relation to other identifiers: In the United States, an ISIN is formed by adding the country code US to the 9-character CUSIP and a final check digit (for example, Apple Inc. common stock has the ISIN US0378331005). ISINs can be mapped to other identifiers such as CUSIPs and SEDOLs to support interoperability in global securities markets.