The International Securities Identification Number (ISIN) is a twelve-digit, alphanumeric code used to identify and track any type of financial security, such as stocks, bonds, derivatives, and other investment instruments, on a global basis. It is recognized as the international standard for uniquely identifying financial and non-financial instruments and is used by most financial services institutions to identify securities. ISINs are managed by National Numbering Agencies (NNAs), organizations authorized and regulated by their respective governments, to identify and assign ISINs to entities in their jurisdictions, as well as to verify the accuracy of the assigned ISINs in the securities databases.

ISINs are essential for efficient reconciliation and reporting of securities as each one is both provisioned to and retrieved from all databases in a standardized format by using the code. This means that the same security can be referenced by its ISIN in any country regardless of where it is incorporated and regardless of the language used to refer to it.

The ISIN code helps to identify the instrument, issuer of the instrument, and the country of incorporation, providing a standardized description or template for each security. This makes trading, settling and reporting of transactions much easier and quicker. It means someone can find the same security, for instance a bond, no matter the jurisdiction it's traded in, and it also simplifies regulatory compliance and prevents securities from inadvertently being classified incorrectly.

In addition, the ISIN is connecting the identifiers of related instruments. This means an ISIN can be used to find related instruments such as options, warrants, underlying shares, and futures. This helps to streamline the process of finding corresponding instruments across multiple jurisdictions.

Today, many countries use the ISIN system to identify investment and financial instruments. This includes the United States, Canada, Australia and the United Kingdom, who all have designated NNAs appointed by their respective governments to assign ISINs.

In conclusion, the International Securities Identification Number (ISIN) is an industry-standard alphanumeric code for a financial instrument, used to uniquely and accurately identify any number of securities worldwide. It is administered by each country's respective National Numbering Agency (NNA), and its use is mandated by various regulatory bodies and exchanges. The ISIN system is used to identify related instruments, improve operational efficiency and reduce areas for fraudulent activity.