The world's biggest and arguably best known company is US0378331005. But even Apple's millions of die-hard fans would be hard pushed to know that is the unique identifier for the company's shares on Nasdaq.
How about US0231351067? Another 12-digit alphanumeric code – this time for Amazon's ordinary shares. Or GB0007980591 for BP shares or CH0031240127 for a vanilla fixed-coupon bond issued by BMW Australia in Switzerland?
The international securities identification number, or ISIN, has been in use for 40 years, appearing on issuance documents and helping smooth cross-border trading and settlement for all securities. It has helped harmonise global standards and opened the door for local investors to access global markets.
Before ISINs, countries coded their own shares and bonds and nothing matched. In the 1970s, officials from Russia, Switzerland, Germany, the US and the UK started discussing harmonising standards, and in November 1981 the first ISIN was published.
After a slow start, interest picked up in the early 1990s as cross-border trading activity increased. Twenty-two national numbering agencies then set up the Association of National Numbering Agencies in early 1992 to harmonise and coordinate efforts – and Tuesday marked the 30th anniversary of ANNA.
There are now 81.4 million ISINs in circulation and Brussels-based ANNA has 119 members and partners and allocates ISINs for more than 200 jurisdictions – effectively every country in the world.
"The ISIN enables markets to speak a common language," said Uwe Meyer, a co-founder and executive director of ANNA. "[Cross-border trading] would be more or less impossible without a common identifier.
"The ISIN is unique in all jurisdictions, it has the same identity all over the world, so it means everybody knows they are talking about the same financial instrument and the same features," he told IFR.
The ISIN uniquely identifies a fungible security, including shares, debt instruments, warrants, derivatives and other securities such as commodities, currencies or indices. The ISIN is included on any issuance papers or other documents to identify it, and is then used by financial firms for trading and settlement purposes.
ISINs are based on ISO 6166, a global standard created for financial instruments. A national numbering agency, or NNA, creates the alphanumeric ID for each security, and ANNA puts all new and amended ISINs into a central database each day and provides that consolidated data to the market.
Each ISIN has a country identifier, followed by a nine-digit national number, which identifies the security. It ends with a single check digit. For the nine-digit number in the middle, NNAs typically use a random number.
"That federated system is one of the strengths of ANNA and the system. The national numbering agencies are the experts, they know everything about the financial instruments and the securities and the features, and have access to all the information needed to describe, classify or identify it," said Meyer.
He said ANNA has been flexible to evolving markets. At present, that includes adapting to the growing use of digital assets, such as for security tokens and cryptocurrencies.
"We are working on guidelines as a first step to allocating ISINs to digital assets," said Meyer, adding that a working group is developing guidelines for standards in digital assets.
Past challenges included adapting to structured products in the early 2000s and expanding to the identification of OTC derivatives, which started in 2017.