About International Securities Identification Number (ISIN)

The ISIN standard is used worldwide to identify specific securities such as bonds, stocks (common and preferred), futures, warrant, rights, trusts, commercial paper and options. ISINs are assigned to securities to facilitate unambiguous clearing and settlement procedures. They are composed of a 12-digit alphanumeric code and act to unify different ticker symbols “which can vary by exchange and currency” for the same security. In the United States, ISINs are extended versions of 9-character CUSIP (Committee on Uniform Security Identification Procedures) numbers; ISINs can be formed by adding a country code and check digit to the beginning and end of a CUSIP, respectively.

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    There are three parts to an ISIN as exemplified by US-049580485-1 (the dashes don't count, they are there to add clarity). The code can be broken down as follows:

  • A two-letter country code, drawn from a list (ISO 6166) prepared by the International Organization for Standardization (ISO). This code is assigned according to the location of a company's head office. A special code, 'XS'. is used for international securities cleared through pan-European clearing systems like Euroclear and CEDEL. Depository receipt ISIN usage is unique in that the country code for the security is that of the receipt issuer, not that of the underlying security.
  • A nine-digit numeric identifier, called the National Securities Identifying Number (NSIN), and assigned by each country's or region's . If a national number is composed of less than nine digits, it is padded with leading zeros to become a NSIN. The numeric identifier has no intrinsic meaning it is essentially a serial number.
  • A single check-digit. The digit is calculated based upon the preceding 11 characters/digits and uses a sum modulo 10 algorithm and helps ensure against counterfeit numbers.


ISINs were once considered only a secondary form of security identification, used exclusively for clearing and settlement. In recent years, some European countries have adopted ISINs as their primary security identifier. An offering memorandum or an prospectus is often required to obtain an ISIN.  ISIN's are implicitly used in the U.S. and Canada because they are built upon CUSIP numbers. Over time, most countries appear willing to adopt ISIN numbering either as a primary or secondary identifier to administer ISINs.

CUSIP (owned by the American Bankers Association and operated by Standard & Poor's) and its work with a CUSIP number. Similarly in the U.K., the Stock Exchange Daily Official List (SEDOL). has no affiliation with either organization. In additon, has no affiliation with the association of national number agencies, (ANNA) or any national number agency (NNA).

Universal acceptance of ISIN is important in meeting the goal of global straight-through processing (GSTP), which is the electronic handling of the trade clearing and settlement without manual intervention. ISINS are used by share custodians to track holdings of institutional investors in a format which is consistent across markets worldwide.


ISINs were first used in 1981, but didn't reach wide acceptance until 1989, when the G30 countries recommended adoption. A year later it was endorsed by the ISO. The Global ISIN Access Mechanism was developed in 1994 to facilitate the electronic exchange of ISIN information across the different regions. Annais charged with the implementation and availability of ISIN throughout the world. To that end, they have worked out an information exchange process named GIAM-2, which uses the Internet and CD-ROM technologies.

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