What are a CIK, an accession number and a file number on EDGAR?

Information as of 16 October 2026. Everything below comes from the SEC's pages on searching EDGAR and accessing EDGAR data, linked below. If anything here is wrong, tell us at contact@oqro.io and we will correct it.

What is a CIK?

The SEC's search page explains that the Central Index Key is a unique identifier assigned to every entity that submits filings on EDGAR, companies and individuals alike, so that a filer can be found whatever name it uses. A CIK has up to ten digits and is shown with leading zeros in EDGAR's own addresses. An insider who is an officer at two companies has one CIK and files Forms 4 for both; a company keeps its CIK through name changes, which is why an old name appears in the filer's former names list rather than as a second filer. OQRO uses the CIK as the identity of a person across companies and of a company across tickers.

How is an accession number built?

The SEC's page on accessing EDGAR data describes the accession number as the unique identifier of each submission, in the form of three groups of digits separated by hyphens. The first ten digits are the CIK of the entity that submitted the filing, which is often a filing agent or a law firm rather than the company itself; the next two are the year of submission; the last six are a sequence number for that submitter in that year. 0001234567-26-000123 is therefore the 123rd submission of filer 1234567 in 2026. Each submission's documents live in a folder named by the accession number, and the index of that folder lists every document inside: the primary form, the exhibits, the XBRL data and the graphics. A Form 4 and its amendment are two submissions with two accession numbers; the amendment says which filing it amends.

What is a file number?

A file number identifies a registration rather than a filing. The prefix says which: 001- for a class of securities registered under Section 12(b) (listed on an exchange), 000- for a class registered under Section 12(g), 333- for a registration statement under the Securities Act, 811- for an investment company. A company that has listed shares and has sold securities in registered offerings has several file numbers, and each of its reports cites the Exchange Act file number on its cover. Section 16 filings cite the issuer's file number so EDGAR can group them under the company as well as under the insider.

How does OQRO link a trade to its document?

Every trade on OQRO carries the accession number of the filing it was read from, and the View original filing link opens that submission's index on EDGAR. A company page lists the company's own filings by accession number; a person page lists the person's. When the same transaction appears in two filings, for example a Form 4 and a later Form 4/A, OQRO keeps the amended version and links both. Our articles on finding insider trades on EDGAR and on EDGAR RSS alerts show how to use the identifiers on the SEC's site directly.

What this does not tell you

A CIK does not say what kind of entity the filer is, and a filer agent's CIK in an accession number is not the company's. A file number says that a registration exists, not that it is current, and a 333- number may belong to an offering that was never completed, or to one that closed years ago. The sequence in an accession number is the agent's, so consecutive numbers may belong to different companies, and a filing withdrawn or rejected keeps its number without appearing in the public index. OQRO describes the filing and its dates; it does not interpret the event or predict anything about a price. Nothing here is investment advice.