International Securities Identification Number (ISIN)

What is an ISIN?

An International Securities Identification Number (ISIN) is a unique, 12-character alphanumeric code used to identify a specific security globally. ISINs create a standard identifier for securities that supports accurate tracking, clearing, settlement, and recordkeeping across markets.

ISIN structure

An ISIN consists of 12 characters:
* First two characters: the ISO 3166-1 alpha-2 country code of the issuer (letters).
* Middle nine characters: a National Securities Identifying Number (NSIN) assigned by the country’s National Numbering Agency (NNA) — often numeric and generated per local rules.
* Final character: a check digit calculated from the preceding characters to help detect errors.

Example formats (for readability only — real ISINs contain no dashes):
* US-000402625-0 → US0004026250
* NA-000K0VF05-4 → NA000K0VF054

Who issues ISINs?

National Numbering Agencies (NNAs) in each country assign ISINs. In the United States, the CUSIP Service Bureau issues ISINs by extending the 9-character CUSIP with a country code and check digit. The structure and assignment rules are defined by ISO 6166.

What securities can receive an ISIN?

Most tradable instruments can be assigned an ISIN, including:
* Equities (ordinary shares, depositary receipts)
* Debt instruments (bonds, commercial paper, T-bills)
* Derivatives and warrants
* Units of investment funds
* Commodities and currencies (when appropriate)

Primary uses and benefits

• Provides a unique, universal identifier so the same security is recognized consistently across exchanges and platforms.
• Facilitates global straight-through processing (STP) for electronic trade clearing and settlement.
• Simplifies cross-border reporting, custody, and position-keeping for institutional investors.
• Reduces operational errors and helps prevent counterfeiting or misidentification of securities.

ISIN vs. ticker symbol vs. CUSIP

• Ticker symbol: Exchange-specific shorthand for a listed security (may vary by exchange and are not globally unique).
• ISIN: A single, global identifier for a specific security — unique worldwide.
• CUSIP: A nine-character identifier used in the U.S. and Canada; ISINs for U.S. securities typically embed the CUSIP as the NSIN portion.

In short: many tickers can map to one ISIN, and a CUSIP can form the middle of a U.S. ISIN.

Brief history and standards

ISINs were introduced in the early 1980s and adopted more broadly after recommendations in the late 1980s. The ISO standard that defines ISINs is ISO 6166. Systems for sharing ISIN data internationally evolved in the 1990s to support electronic exchange and reconciliation of identifiers.

How to find an ISIN

• For publicly listed securities, an ISIN may appear on the stock certificate, prospectus, or in regulatory filings.
• Financial data vendors, exchanges, custodians, and NNAs publish ISINs for issued securities.
• Lookup tools from NNAs or authorized data providers can resolve securities to their ISINs.

Key takeaways

• ISINs are 12-character, globally unique identifiers for securities that improve clarity and efficiency in cross-border trading and settlement.
• They are issued by national numbering agencies and defined by ISO 6166.
• ISINs are distinct from exchange-specific tickers and are often related to national identifiers such as CUSIP in the U.S.

The ISIN system underpins much of the operational infrastructure for modern international securities markets, enabling reliable identification and straight-through processing across jurisdictions.