An International Securities Identification Number (ISIN) is a 12-character alphanumeric code that uniquely identifies a specific security globally. ISINs are standardized by ISO 6166 and are used across financial systems worldwide for unambiguous security identification.
Structure
ISINs have a fixed format:
- Characters 1-2: Country code (ISO 3166-1 alpha-2)
- Characters 3-11: National Securities Identifying Number (NSIN)
- Character 12: Check digit (using the Luhn algorithm)
Example: GB0002374006
- GB: United Kingdom
- 000237400: SEDOL code
- 6: Check digit
Key Characteristics
- Global uniqueness: Each ISIN is unique worldwide
- Permanence: ISINs remain fixed throughout the security's life
- Scope: Covers equities, bonds, derivatives, and other financial instruments
- Mandatory: Required for cross-border trading and reporting
Usage
ISINs are the primary identifier in:
- Internal system databases and APIs
- Cross-border settlements and clearing
- Regulatory reporting (MiFID II, EMIR)
- Reference data management
- Transaction reporting