Международный идентификационный номер ценной бумаги (ISIN)

Identifier for a security

An International Securities Identification Number (ISIN) is a code that uniquely identifies a security globally for the purposes of facilitating clearing, reporting and settlement of trades. Its structure is defined in ISO 6166. The ISIN code is a 12 character alphanumeric code that serves for uniform identification of a security through normalization of the assigned National Number, where one exists, at trading and settlement.

ISINs were first used in 1981, but did not reach wide acceptance until 1989, when the G30 countries recommended adoption. The ISIN was endorsed a year later by ISO with the ISO 6166 standard. Initially information was distributed via CD ROMs and this was later replaced by distribution over the internet.

Since 1989 they slowly gained traction worldwide in their usage. ISINs were introduced worldwide and became the most popular global securities identifier. Trading, clearing and settlement systems in many countries adopted ISINs as a secondary measure of identifying securities. Some countries, mainly in Europe, moved to using the ISIN as their primary means of identifying securities. In addition the European regulations such as Solvency II Directive 2009 increasingly require the ISIN to be reported.

In 2004 the European Union mandated the use of instrument identifiers in some of its regulatory reporting, which included ISIN as one of the valid identifiers.

The ISIN is generally included in services sold by financial data vendors and intermediaries. These services are normally paid services as more value added data is included with the information. In general, the issuer of a security will include the ISIN in issuance papers or other documentation for identification purposes.

In 2009, Standard & Poor's was charged by the European Commission (EC) with abusing its position in licensing international securities identification codes for United States securities by requiring European financial firms and data vendors to pay licensing fees for their use. "This behaviour amounts to unfair pricing," the EC said in its statement of objections which lays the groundwork for an adverse finding against S&P. "The (numbers) are indispensable for a number of operations that financial institutions carry out – for instance, reporting to authorities or clearing and settlement – and cannot be substituted". In 2011, Standard and Poor's provided six undertakings to the European Commission to remedy the situation. The agreement is applicable to all consuming companies in the European Economic Area. These expired at the end of 2016.

The examples below describes one approach for applying the Luhn algorithm on two different ISINs. The difference in the two examples has to do with if there are an odd or even number of digits after converting letters to number. Since the NSIN element can be any alpha numeric sequence (9 characters), an odd number of letters will result in an even number of digits and an even number of letters will result in an odd number of digits. For an odd number of digits, the approach in the first example is used. For an even number of digits, the approach in the second example is used. The Luhn algorithm can also be applied in the same manner for both types or lengths (alternating multiply the string of digits by 1 and 2, starting from the end of the string), being more generic.