CUSIP vs ISIN: the two security identifiers
On CUSIP vs ISIN, both are codes that identify a security, but they work at different scopes. A CUSIP identifies a security in the United States and Canada in nine characters. An ISIN identifies a security anywhere in the world in twelve, and for a US security it is built around the CUSIP. This guide compares CUSIP vs ISIN so you know which is which and how they fit together. It is not investment advice.
Definition
A CUSIP versus an ISIN
are two security identifiers at different scopes. A CUSIP is a 9-character code for US and Canadian securities. An ISIN is a 12-character global code under ISO 6166. A US ISIN is the CUSIP wrapped with a country code and a check digit. Source: CUSIP Global Services, ISO.
What is a CUSIP?
A CUSIP is a 9-character identifier for a security issued in the US or Canada, assigned by CUSIP Global Services on behalf of the American Bankers Association. Its first six characters identify the issuer, the next two the issue, and the last is a check digit. US institutional filings such as the 13F list holdings by CUSIP.
What is an ISIN?
An ISIN is a 12-character identifier defined by ISO 6166 and used worldwide. It begins with a two-letter country code, then a nine-character national number, then a check digit. In India, NSDL allots ISINs and company codes carry the INE prefix.
How do the two identifiers relate?
They are not competitors so much as nested layers. For a US security, the ISIN is literally the CUSIP with US in front and a check digit behind.
| What to check | CUSIP | ISIN |
|---|---|---|
| Length | 9 characters | 12 characters |
| Scope | US and Canada | Global (ISO 6166) |
| Standard | CUSIP Global Services | ISO 6166 |
| India | Not used | INE-prefixed, allotted by NSDL |
| Relationship | Sits inside a US ISIN | Wraps the CUSIP for US securities |
9 inside 12
How they nest: a US ISIN is the 9-character CUSIP plus a country code and a check digit
Source: CUSIP Global Services, ISO
Why this matters for reading filings
Matching a holding to a company depends on the identifier the filing uses. A US 13F filing uses CUSIPs, while an Indian shareholding pattern works off ISINs. For the entity behind the security, rather than the security itself, see what a legal entity identifier is.
Flock reads disclosure filings across the US and India and resolves each identifier back to the right security, dated and linked to its source. What any of it means for you is your call to make.
Frequently asked questions
What is the difference between a CUSIP and an ISIN?
A CUSIP is a 9-character identifier for a security issued in the US or Canada. An ISIN is a 12-character global identifier under ISO 6166. For a US security, the ISIN is built by wrapping the CUSIP with a country code and a check digit. Source: CUSIP Global Services, ISO.
Does a US ISIN contain the CUSIP?
Yes. A US ISIN starts with the country code US, then the 9-character CUSIP, then a check digit, for 12 characters in total. So a US security has both, and the CUSIP sits inside its ISIN. Source: ISO, CUSIP Global Services.
Which identifier does India use?
India uses the ISIN. NSDL allots ISINs for Indian securities, except government securities, which the Reserve Bank of India handles. Indian company ISINs carry the INE prefix. India does not use CUSIPs. Source: NSDL, RBI.
Where do these identifiers show up?
US filings such as a 13F identify holdings by CUSIP. Indian filings and demat records identify securities by ISIN. Matching a holding to the right company means resolving whichever identifier the filing uses. Source: SEC, NSDL.
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.