What is an ISIN? The 12-character security code (2026)
An ISIN, or International Securities Identification Number, is the 12-character code that identifies a security anywhere in the world. It is the identifier you see on an Indian contract note or demat statement, and the one that lets a single stock be recognised across borders. This guide explains what an ISIN is, how it is structured, and who allots it. It is not investment advice.
Definition
An ISIN
is a 12-character alphanumeric code that uniquely identifies a security worldwide, defined by the ISO 6166 standard. It begins with a two-letter country code, then a nine-character national number, then a single check digit. In India, NSDL allots ISINs for most securities. Source: ISO, NSDL.
How is an ISIN structured?
An ISIN is built in three parts across its 12 characters:
- Characters 1 and 2 the country code, such as IN for India or US for the United States.
- Characters 3 to 11 the national security number assigned by that country's numbering agency.
- Character 12 a check digit calculated over the rest of the code.
For an Indian company, the third character is E, so equity ISINs carry the familiar INE prefix. Mutual fund units use INF. The characters after that identify the company, the security, and the instrument type.
Who allots ISINs in India?
SEBI has authorised the National Securities Depository Limited (NSDL) to act as the national numbering agency and allot ISINs for Indian securities under the ISO 6166 standard. Government securities are the exception: the Reserve Bank of India allots the ISIN for those. This is why every dematerialised Indian security has one ISIN that stays with it across exchanges and depositories.
12 characters
Length of an ISIN under ISO 6166: two-letter country code, nine-character national number, one check digit
Source: ISO, NSDL
Why ISINs matter for reading filings
An ISIN is the anchor that ties a security to its filings. When you read an Indian shareholding pattern or track which mutual funds are buying a stock, the ISIN is what matches a holding to the right company even when names or tickers vary.
The US equivalent is the CUSIP, and a US ISIN is built around it. For the comparison, see CUSIP vs ISIN and what a CUSIP is. For the entity identifier used alongside ISINs in regulatory reporting, see what a legal entity identifier is.
Flock reads disclosure filings across India and the US and keeps each security matched to its identifier, dated, and linked to its source. What any of it means for you is your call to make.
Frequently asked questions
What is an ISIN?
An ISIN is a 12-character alphanumeric code that uniquely identifies a security worldwide, defined by the ISO 6166 standard. It starts with a two-letter country code, followed by a nine-character national number and a check digit. Source: ISO, NSDL.
Who allots ISINs in India?
SEBI has authorised NSDL as the national numbering agency to allot ISINs for Indian securities, except government securities, for which the Reserve Bank of India allots the ISIN. Indian company ISINs begin with the prefix INE. Source: NSDL, SEBI, RBI.
What does an Indian ISIN look like?
An Indian equity ISIN begins with IN for India and E for a company, giving the INE prefix, followed by a company identifier, a security code, and a check digit, for 12 characters in total. Mutual fund units use INF. Source: NSDL.
Is an ISIN the same as a CUSIP?
No. An ISIN is a 12-character global identifier under ISO 6166. A CUSIP is a 9-character identifier for US and Canadian securities. A US ISIN embeds the CUSIP inside it. Source: ISO, CUSIP Global Services.
Flock tracks these filings, sourced, dated, and linked back to the original. See what smart-money entities disclosed, without the guesswork about what it means.
Disclosures shown are public regulatory filings. Data may be delayed or incomplete. Smart-money entities may no longer hold positions shown. Not investment advice.