“Corporate identification number” can mean different things in the United States. It may refer to a federal Employer Identification Number (EIN), a state-issued business or filing number, or a public company’s SEC Central Index Key (CIK). The right number depends on who is asking and what the number will be used for. Checking the request, then searching the appropriate official records, can help locate the correct number without sharing sensitive information unnecessarily.
What a Corporate Identification Number Means
The United States does not have one universal corporate identification number assigned to every business. Federal agencies, state governments, and securities regulators maintain different identifiers for different purposes. A bank, vendor, tax form, or state filing may use the phrase “corporate ID” to mean a number issued by a particular agency.
Before searching, check the form, email, or instructions that request the number. Look for terms such as “EIN,” “federal tax ID,” “state entity number,” “file number,” or “CIK.” If the request only says “corporate identification number,” ask the requester which agency’s number is required and whether a specific format is expected. This can prevent submitting the wrong identifier.
| Identifier | Who issues it | Common use |
|---|---|---|
| Employer Identification Number (EIN) | Internal Revenue Service (IRS) | Federal taxes, payroll, banking, and many business forms |
| State entity or filing number | State business filing agency, often the Secretary of State | State business records, annual reports, and licensing |
| Central Index Key (CIK) | U.S. Securities and Exchange Commission (SEC) | Identifying filers and disclosures in SEC systems |
How to Find a Company’s EIN
An EIN is a federal tax identification number issued by the IRS to identify a business or other entity for tax administration. It has nine digits, commonly displayed as XX-XXXXXXX. Businesses often need it for federal tax filings, payroll, opening business bank accounts, and certain applications. An EIN is not the same as a Social Security number, state business number, or SEC CIK.
Check the Business’s IRS Confirmation
The most direct place to look is the original IRS notice confirming the EIN assignment, often called the CP 575 notice. A business may also have an EIN verification letter, such as an IRS Letter 147C, obtained later. Search the company’s secure files, tax records, and correspondence for “EIN,” “Employer Identification Number,” “CP 575,” or “147C.” These documents are generally more reliable than an old spreadsheet or an unverified online listing.
Review Tax and Banking Records
An EIN may appear on federal business tax returns, payroll tax filings, or other IRS correspondence. It may also be recorded in business banking documents, accounting software, payroll records, and applications submitted to vendors or government agencies. Access should be limited to people authorized to handle the company’s tax and financial information.
Some tax forms show an organization’s EIN, including certain versions of Form W-2, Form 1099, and business income tax returns. However, a copy belonging to a customer, contractor, employee, or another business may not be available to the company searching. The EIN should be taken from an authorized company record, not inferred from unrelated documents.
Ask an Authorized Person
If the number is not in the records, contact the company’s owner, finance department, payroll administrator, tax preparer, or authorized representative. A former accountant or payroll provider may have it in the company’s files, subject to the terms of the relationship and applicable privacy safeguards. The person requesting the EIN may also be able to confirm whether another identifier would satisfy the requirement.
Contact the IRS If the EIN Is Still Missing
The IRS advises businesses that cannot locate an EIN to check their original assignment notice and previously filed returns, then contact the IRS Business and Specialty Tax Line if necessary. The IRS may verify an EIN with a person authorized to receive that information after confirming identity and authority. Have the legal business name, address, and identifying details available, and use the contact information on the official IRS website.
The IRS generally does not provide a public online lookup tool for retrieving any business’s EIN. A third-party search result should not be treated as an official confirmation, especially if it requests payment or sensitive personal details. For IRS procedures and current contact information, see IRS guidance on lost or misplaced EINs.
How to Find a State Business Identification Number
A state business ID may be called an entity number, document number, charter number, filing number, or registration number. The name and format vary by state. State business filing offices assign or display these identifiers in records for corporations, limited liability companies, partnerships, and other registered entities. A state ID is not a substitute for an EIN, and a company may have separate state identifiers in multiple states.
Search the State’s Official Business Database
Visit the business search website operated by the Secretary of State or the agency responsible for business registrations in the state where the entity was formed. Search by the company’s exact legal name, including punctuation or terms such as “Inc.” or “LLC.” If the first search does not work, try a shortened name or alternate spelling. Many official records show the entity number alongside the legal name, status, formation date, and registered agent.
A company may be registered in its formation state and separately qualified to do business in other states. Those jurisdictions may maintain distinct records and identification numbers. Search the state relevant to the form or transaction rather than assuming the formation-state number will be accepted. State databases are useful for locating public filing information, but they do not necessarily display federal tax identifiers.
Review Formation and Compliance Documents
The state ID may appear on the company’s articles of incorporation or organization, certificate of formation, registration confirmation, annual report, or other filing receipt. It may also be listed in correspondence from the state filing office. Keep these documents in the company’s permanent records so authorized staff can confirm the identifier later.
Some states distinguish a permanent entity number from a document or filing number assigned to a particular submission. If a form asks for a state business ID, use the label and instructions provided by that state or requesting organization. When the database displays several numbers, contact the filing office rather than guessing which one applies.
How to Find a Public Company’s SEC CIK
A CIK, or Central Index Key, is an SEC identifier used for filers in the commission’s systems. It is not the same as an EIN or a state registration number. Investors, researchers, and businesses may need a CIK to locate a public company’s regulatory filings. A CIK can also be associated with individuals or other filing entities, so the matching name and filing record should be checked.
Search the SEC’s official company search and EDGAR filing tools using the company name or, when available, its ticker symbol. The company’s filing page displays the CIK and links to submissions such as annual and quarterly reports. The SEC’s EDGAR search is the authoritative place to look for SEC filings and related filer information.
Not every business has a CIK. A privately held company that does not file with the SEC may not appear as a company filer in EDGAR. A ticker symbol is also not a CIK: ticker symbols identify securities for trading, while the CIK identifies a filer in SEC systems.
Which Number Should Be Used?
The correct identifier depends on the purpose of the request. A federal tax form or payroll setup usually calls for the EIN. A state annual report or entity search may ask for the state entity number. A request tied to SEC filings may require the CIK. Banks and other institutions may use “business ID” loosely, so their instructions should be clarified before a number is submitted.
| Request or task | Likely identifier | What to verify |
|---|---|---|
| Federal business tax or payroll paperwork | EIN | Use the IRS-assigned number for the legal entity |
| State formation or annual filing | State entity or filing number | Confirm the state and the exact number label |
| SEC filing research | CIK | Match the CIK to the correct filer in EDGAR |
| Bank, vendor, or customer onboarding | Depends on the organization’s instructions | Ask which agency’s identifier is required |
Businesses can have several identifiers at once. For example, a corporation may have an EIN for federal tax administration, a state entity number in its formation state, additional registrations in states where it operates, and a CIK if it files with the SEC. These numbers serve different systems and should not be interchanged simply because a form uses a general phrase such as “corporate ID.”
Common Problems When Searching
The Search Uses a Trade Name
A company may operate under a trade name, assumed name, or “doing business as” name that differs from its legal entity name. State databases and tax records may use the legal name. Search both names, and check the company’s formation documents or business registration for the connection between them.
The Business Has Changed Its Name or Structure
Companies can change names, merge, convert, dissolve, or form a new legal entity. A name change may leave some identifiers unchanged, while creating a new entity may require new registrations and potentially a new EIN depending on the circumstances. The IRS explains when a business needs a new EIN; consult its guidance rather than assuming that a prior entity’s number carries over.
The Company Operates in More Than One State
Businesses that operate outside their formation state may register as foreign entities in other states. “Foreign” in this context generally means formed in a different state or jurisdiction, not necessarily outside the United States. Each state’s public records may show a separate registration number, so the appropriate jurisdiction depends on the filing or transaction.
A Database Shows Several Similar Businesses
Common business names can produce multiple search results. Compare the legal name, state of formation, address, entity type, and status before using an identifier. For an SEC filer, compare the company name and filings in EDGAR. A matching name alone may not be enough to establish that a record belongs to the right business.
Protect Business Identification Numbers
An EIN is not designed to be secret in the same way as a password, and it may appear on legitimate tax and business documents. Still, it can be misused in fraud or identity theft. Share it only with organizations that have a valid business need, use secure submission methods, and avoid sending tax documents through unprotected channels. Do not post documents containing an EIN publicly unless the information has been properly reviewed and redacted.
State entity numbers and CIKs are generally available in public records, but access to public information does not make every associated document safe to share. Formation records, tax returns, bank statements, and account credentials can contain additional sensitive information. Organizations should follow their document-retention policies and restrict access based on job responsibilities.
Official Sources to Check
- IRS: Lost or misplaced EIN — steps for locating an existing EIN and contacting the IRS when needed.
- IRS: Do you need a new EIN? — guidance on whether certain changes require a new federal number.
- SEC EDGAR search — official search for SEC filers and company disclosures.
- USA.gov: State business resources — starting point for finding state business agencies and registration information.
When the exact identifier remains unclear, the safest next step is to ask the requesting organization which number it accepts. That confirmation can save time, prevent filing errors, and reduce the risk of disclosing a tax identifier when a public state or SEC number would have been sufficient.