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What Is a CIK Number? The SEC Central Index Key, Explained
Updated 2026-08-05. What a CIK is, why it is a more reliable key than a ticker, the zero-padding trap that breaks lookups, and the part most explanations leave out — individual people have CIKs too.
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A CIK (Central Index Key) is the unique identifier the SEC assigns to every entity that files with EDGAR — public companies, investment funds, institutional managers, and individual corporate insiders. It is up to ten digits, often written zero-padded (Apple is 320193, also written 0000320193). Unlike a ticker, a CIK is permanent: it does not change when a company rebrands, changes ticker, or moves exchange.
What a CIK is
EDGAR — the SEC's electronic filing system — needs a way to tell filers apart that does not depend on names, which are duplicated, abbreviated and changed constantly. The Central Index Key is that key. Every entity that has ever filed anything with the SEC has exactly one, assigned the first time it files.
CIKs are handed out sequentially, so the number encodes rough seniority. Coca-Cola, filing since the earliest days of EDGAR, is 21344. Alphabet, created as a holding company in 2015, is 1652044. That ordering is a useful sanity check: a five-digit CIK on a company founded last year is a data error.
Why a CIK beats a ticker
A ticker identifies a security on a particular exchange. A CIK identifies the filing entity. That difference matters more than it sounds:
- Tickers get reassigned. When a company delists, its symbol can be handed to an unrelated company later. A historical series keyed on ticker will silently splice two businesses together.
- Tickers change. Rebrands and exchange moves change the symbol while the filer stays the same. The CIK does not move.
- Not every filer has a ticker at all. Individual insiders, private funds and institutional managers file constantly and have no symbol.
For anything historical or anything involving people, key on the CIK and treat the ticker as a display label. This is the single most common cause of quietly wrong insider-trading datasets.
People have CIKs too
Most explanations of the CIK stop at companies. That leaves out the half that matters for insider analysis: every officer, director and 10% owner gets their own CIK the first time they file a Form 3, 4 or 5.
A personal CIK follows the individual, not the employer. If a CFO leaves one public company for another, the filings at both are attached to the same personal CIK. That is what makes it possible to ask questions like “how has this person's buying performed across their whole career, not just at their current company?” — a question you cannot answer keyed on ticker.
Form4API indexes insiders by personal CIK for exactly this reason. Every profile on the insider directory is keyed to one, and the insider leaderboard ranks people across every company they have ever filed at.
The zero-padding trap
This is the one that costs developers real time. EDGAR presents CIKs in two forms interchangeably: the bare integer and a ten-digit zero-padded string. Apple is both 320193 and 0000320193. Some EDGAR endpoints require the padded form, some accept either, and several SEC bulk files mix them.
// the failure mode
If you store CIKs as strings without normalising, the same filer arrives as two distinct keys and quietly becomes two rows — one accumulating filings under 320193, the other under 0000320193. Neither looks wrong on inspection. Both are half-complete. We have hit this in our own pipeline.
The fix: normalise on ingest — store the CIK as an integer, or always zero-pad to ten characters, and never compare the two forms as strings. Pick one and enforce it at the boundary rather than at every call site.
How to look up a CIK
- SEC CIK lookup — the official free search by company or person name, at sec.gov/search-filings/cik-lookup. Partial names work: searching “Bank of” returns every match.
- SEC ticker map — for bulk or programmatic use the SEC publishes a machine-readable ticker-to-CIK file at sec.gov/files/company_tickers.json (10,398 entries as of 2026-08-05). It covers listed companies only — no individuals.
- Form4API — every company and insider record carries its CIK, and insiders are addressable by CIK directly. Covers people, which the SEC ticker map does not.
Example CIKs
Verified against the SEC's own ticker map on 2026-08-05. Both columns refer to the same filer — the padded form is what several EDGAR endpoints expect.
| Ticker | Company | CIK | Zero-padded |
|---|---|---|---|
| AAPL | Apple Inc. | 320193 | 0000320193 |
| MSFT | Microsoft Corp | 789019 | 0000789019 |
| NVDA | NVIDIA Corp | 1045810 | 0001045810 |
| AMZN | Amazon.com Inc | 1018724 | 0001018724 |
| GOOGL | Alphabet Inc. | 1652044 | 0001652044 |
| META | Meta Platforms, Inc. | 1326801 | 0001326801 |
| TSLA | Tesla, Inc. | 1318605 | 0001318605 |
| JPM | JPMorgan Chase & Co | 19617 | 0000019617 |
| WMT | Walmart Inc. | 104169 | 0000104169 |
| KO | Coca-Cola Co | 21344 | 0000021344 |
Each ticker links to its Form4API company profile, where the insider filings for that CIK are listed.
Working with CIKs via the API
Form4API addresses insiders by their personal CIK, so once you have one you can pull a person's full filing history without knowing which companies they worked at.
# The insider record for a personal CIK curl -H "X-Api-Key: $FORM4API_KEY" \ "https://api.form4api.com/v1/insiders/0001124485" # Every transaction that insider has filed, at any company curl -H "X-Api-Key: $FORM4API_KEY" \ "https://api.form4api.com/v1/insiders/0001124485/transactions" # A company profile, addressed by ticker curl -H "X-Api-Key: $FORM4API_KEY" \ "https://api.form4api.com/v1/companies/AAPL"
Padded and unpadded CIKs both resolve — normalisation happens server-side, so you do not have to guess which form an endpoint wants. Full reference in the API docs; the free tier covers 500 requests a day with no card.
FAQ
- What does CIK stand for?
- Central Index Key. It is the unique identifier the U.S. Securities and Exchange Commission assigns to every entity that files with EDGAR.
- How many digits is a CIK number?
- Up to ten. CIKs are assigned sequentially, so older filers have shorter numbers — Coca-Cola is 21344 while Alphabet is 1652044. EDGAR frequently displays and accepts them zero-padded to a full ten digits, so 21344 and 0000021344 are the same filer.
- Do individual people have CIK numbers?
- Yes. Company officers, directors and 10% owners each receive their own CIK when they first file a Form 3, 4 or 5. That personal CIK follows them across every company they are an insider at, which is what makes it possible to track one person’s trading history across employers.
- Is a CIK the same as a ticker symbol?
- No. A ticker belongs to a security and can change or be reassigned to a different company entirely. A CIK belongs to the filing entity and does not change when a company rebrands, changes ticker, or moves exchange. For anything historical, the CIK is the safer key.
- How do I look up a CIK number?
- The SEC runs a free CIK lookup at sec.gov/search-filings/cik-lookup, and publishes a machine-readable ticker-to-CIK map at sec.gov/files/company_tickers.json. Form4API exposes CIKs on every company and insider record via its REST API.
- Can one company have more than one CIK?
- It can end up associated with more than one over time. A CIK identifies a filing entity, not a brand — so reorganisations, holding-company structures and certain mergers create a new entity with a new CIK while the old one remains in EDGAR attached to its historical filings.