Standards
CUSIP
A nine-character identifier used for securities in North American markets.
- Kind
- Identifiers
- Steward
- CUSIP Global Services; American Bankers Association
- Official source
- https://www.cusip.com/
What it describes
CUSIP numbers identify securities and related financial instruments in a widely used North American numbering system. The system is owned by the American Bankers Association and administered by CUSIP Global Services. CUSIPs are common in settlement, reporting, and issuer documents. Their presence in a record identifies a numbered instrument, not every security issued by the same organization or every trading venue on which it appears.
CUSIP data is subject to licensing terms, so a publicly visible number does not imply unrestricted redistribution of a complete reference database. Data users should retain the source of each number and distinguish an issuer-level reference from a particular issue. A syntactically plausible CUSIP also needs validation against authoritative instrument details before two holdings or filings are merged.
Structure
Nine characters: six-character issuer base, two-character issue designation, and a check digit.
Useful for
- Match securities across settlement records.
- Link filings to a specific issue.
- Compare vendor instrument records.
Limits
- Licensing can restrict reference-data use.
- Does not uniquely identify a corporate group.
- A plausible code is not proof of an active issue.
How it is used in practice
CUSIPs are woven into North American post-trade processing. Settlement instructions, custody statements, municipal bond disclosures and issuer filings frequently cite them, so a researcher working from U.S. documents will meet CUSIPs long before meeting any other securities identifier. The code is built from an issuer base and an issue suffix, which makes it convenient for grouping the securities of one issuer, though the base alone is not an entity identifier.
In many U.S. and Canadian instruments the ISIN is constructed by adding a country prefix to the CUSIP and a new check digit, so the two identifiers often travel together. That does not make them interchangeable. The CUSIP is a licensed product of its administrator, and the terms of use shape what a downstream system may store or publish. A record should therefore keep the identifier where its source allows it and record the source, instead of assuming that a number seen in a public document is free for redistribution as part of a larger database.
A worked example
A fictional municipal authority, the Port of Halden, issues a revenue bond. An offering document prints a CUSIP for each maturity. A researcher compiling a table of outstanding bonds finds the same maturity listed in two sources with CUSIPs that differ in the final digits of the issue part. One source is the offering document, the other a secondary aggregator.
The check digit tells the researcher which entry is a possible transcription error: the code that fails the check is almost certainly mistyped. The one that passes is not thereby confirmed, because a transposition can produce another valid code. The researcher confirms against the official statement, records the page and the retrieval date, and notes that the aggregator's entry failed the check digit. In the record, the bond is cited at the sentence in the offering document that lists the maturity and its code, and the aggregator is kept as a discrepant source rather than deleted.
Evaluating a claim that rests on a CUSIP
A CUSIP supports claims about which numbered security a document refers to. It does not support claims about the issuer's identity, the security's current outstanding status or its terms. Before relying on a code, look for the issuing document or the administrator's record, and treat a bare code in a spreadsheet as a pointer waiting for confirmation.
Look also at how the code travelled. Codes lose leading zeros in spreadsheets, gain stray characters when copied from PDFs, and are sometimes confused with the six-character issuer base. Systems that normalize them should keep the original string beside the normalized form. When two datasets disagree about a CUSIP for the same bond, the disagreement is evidence of a data-quality problem in at least one of them, and the resolution deserves a recorded basis: which source was preferred and why, not simply which one the pipeline happened to read last.
Confusions to avoid
A CUSIP is not an ISIN, although a U.S. ISIN often embeds a CUSIP. It is not a CIK, which identifies a filer in EDGAR rather than a security. It is not a ticker. And it is not an issuer identifier, even though the first six characters identify the issuer within the CUSIP system. Using the six-character base as a proxy for a company is tempting and unsafe: corporate actions, acquisitions and reissuance can leave one company with several bases and one base associated with a different company later.
A final confusion concerns the permanence of the code. A security keeps its CUSIP through ordinary life, but a reorganization, a stock split with a new share class or a change of issuer can produce a new code. Historical analyses need the code as it stood at each date, plus a dated link between old and new codes. Replacing the old code with the new one in place destroys the evidence on which the link rests.
Questions a reviewer can ask
Does the check digit validate? Was the code taken from an issuing document, a custodian statement or an aggregator? Is the base for the issuer, and the suffix for the issue, consistent with the document's description of the security? Do the licence terms of the source allow the code to be stored and shown to the intended readers? If two codes appear for one bond, is there a record of a reissuance or a correction, and when did it take effect?
Found an error on this page? See corrections for what counts as one, how to report it and the dated log.
Enquiry
Which of your sources carry CUSIP?
Tell us which sources carry it, which key the same entity some other way and who may read which. We reply with whether and how a first record would use this identifier.
Or write to [email protected] in your own words.