An International Securities Identification Number (ISIN), also called the ISIN number, is a code of 12 letters and digits that identifies one security, such as a share, bond, debenture or mutual fund unit. It starts with a two letter country code, then nine characters for the security and one check digit, and no two securities share a code.
The code follows the international standard ISO 6166, so an Indian code is built in the same way as the code of any other country. Each security has its own code, and the format can be seen in INE123A01016 which is given here as a format example only.
NSDL, CDSL and the RBI: who allots an ISIN and its structure
For Indian securities, the code begins with IN, the country code. The middle part identifies the security, and the last character is a check digit generated by the system to prevent errors and fraud in securities transactions.
The middle part is generated by the National Numbering Agency, a role performed in India by National Securities Depository Limited (NSDL), and Central Depository Services (India) Limited (CDSL) also allots codes as a depository. Both allot codes for securities other than government securities, while the RBI allots the codes for government securities.
A company applies through its registrar and transfer agent (RTA) registered with SEBI is the statutory regulator of India's securities market, with the legal duty to protect investors and to promote and regulate that market. Read the full meaning of SEBI, and a separate code is allotted for each class of security to be dematerialised.
An ISIN identifies one security, unlike an exchange ticker
Each code belongs to one security, so a demat holding, a trade and a depository record can be matched to the same share, bond or fund unit. The check digit helps catch typing errors.
An ISIN is different from the ticker, or trading symbol, used on NSE and BSE. A ticker symbol is the exchange trading code and can differ between exchanges, while the ISIN is the single code for the security.