Whether a tax ID is public information depends entirely on which tax ID you mean. Social Security numbers and Individual Taxpayer Identification Numbers are confidential by federal law and cannot be looked up through any government database. Employer Identification Numbers are different: the IRS does not publish them in a general directory, but they appear routinely in filings that anyone can read, so for many businesses the EIN is effectively semi-public.
SSNs and ITINs Are Confidential
Your SSN is the nine-digit number the Social Security Administration issues to track earnings and calculate retirement benefits.1Social Security Administration. Meaning of the Social Security Number An ITIN is the nine-digit number the IRS issues to people who have to file a U.S. tax return but can’t get an SSN.2Internal Revenue Service. Individual Taxpayer Identification Number (ITIN) Both get the same confidentiality treatment.
Two federal statutes do the heavy lifting. The Privacy Act of 1974 prohibits federal agencies from disclosing records retrieved by personal identifiers, including SSNs, without the individual’s consent unless a specific statutory exception applies.3Social Security Administration. The Privacy Act of 1974 The Social Security Act separately bars SSA employees from disclosing any file, record, or report about a person obtained during their duties except where federal law allows it.4Social Security Administration. Submit a Privacy Act Request for Your or Another Persons Records – Privacy Program
On the tax side, Section 6103 of the Internal Revenue Code makes tax returns and “return information” confidential. That phrase covers any data the IRS collects in connection with a return, including the ITIN or SSN on it. Federal and state employees with access are barred from disclosing it, with narrow exceptions for things like law enforcement and specific intergovernmental data-sharing agreements.5Office of the Law Revision Counsel. 26 USC 6103 – Confidentiality and Disclosure of Returns and Return Information
At least a dozen states layer their own rules on top, limiting how private companies can use or display SSNs. Common prohibitions include printing an SSN on mailed documents, publicly posting it, or requiring it as a website login.
The practical result: no one can type your name into a government lookup and retrieve your SSN or ITIN, and a federal employee who hands one out without authorization is committing a crime.
EINs Are a Different Story
An Employer Identification Number identifies a business entity, not an individual, and the IRS treats it accordingly. There is no general public search tool where you can type a company name and get its EIN. But EINs appear so often in documents that are themselves public that for whole categories of organizations the number is easy to find.
The widest window is nonprofits. Tax-exempt organizations must make their Form 990 annual returns available for public inspection, and the EIN is printed on those returns.6Internal Revenue Service. Public Disclosure and Availability of Exempt Organization Returns and Applications – Public Disclosure Overview The IRS runs a Tax Exempt Organization Search where anyone can look up a nonprofit by name or EIN and open its filings.7Internal Revenue Service. Search for Tax Exempt Organizations
Publicly traded companies expose their EINs through SEC filings. The number appears on the cover page of Form 10-K annual reports and Form 10-Q quarterly reports, all searchable through EDGAR.8SEC.gov. EDGAR Full Text Search State business registrations such as articles of incorporation and annual reports filed with a Secretary of State often include the EIN too, though the practice varies by state.
Private, for-profit businesses are the hard case. There is no nonprofit-style search tool, and IRS confidentiality rules still cover the agency’s own records about them. Even so, businesses hand their EIN to vendors, banks, and payers so often that it carries nothing like the secrecy around an SSN.
How to Look Up a Business EIN
Your approach depends on the type of entity.
- Nonprofits: use the IRS Tax Exempt Organization Search at irs.gov. You can search by name or EIN and open Form 990 filings going back years. Third-party databases like Candid (formerly GuideStar) host the same filings and let you search by name, location, or EIN.7Internal Revenue Service. Search for Tax Exempt Organizations9Candid. Where Can I Find an Organizations Form 990 or 990-PF
- Publicly traded companies: search EDGAR for the company’s most recent 10-K or 10-Q and look at the cover page, where the EIN is usually labeled “IRS Employer Identification Number” or similar.
- Private businesses: no federal lookup exists. State business registration records sometimes include the EIN, but the most reliable move is asking the business directly. If you’re paying them for work that requires tax reporting, they have to give you the EIN on a Form W-9 anyway.
When You Have to Share Your Own Tax ID
Confidentiality doesn’t mean you get to keep your TIN to yourself. Federal regulations require every person filing a return, statement, or other tax document to include their TIN, and anyone who needs it for their own tax reporting can require you to provide it.10eCFR. 26 CFR 301.6109-1 – Identifying Numbers
Form W-9 and Information Returns
The most common trigger is Form W-9. When you work as an independent contractor, earn interest or dividends, or receive certain other payments, the payer needs your TIN so they can file information returns like the 1099-NEC or 1099-INT.11Internal Revenue Service. About Form W-9, Request for Taxpayer Identification Number and Certification Refuse or give an incorrect TIN and the payer must withhold 24% of your payments and send that to the IRS as backup withholding. It isn’t a penalty; it’s a credit against your taxes. But it ties up your money until you file and claim it back.
Banking
Banks and other financial institutions collect your TIN when you open an account, and that is not optional. Under Bank Secrecy Act regulations, covered financial institutions must also identify and verify any natural person who owns 25% or more of a legal entity opening an account.12FinCEN.gov. Information on Complying with the Customer Due Diligence (CDD) Final Rule
Employment
Your employer collects your SSN for payroll tax reporting. FTC guidance expects businesses to use SSNs only for lawful purposes like tax reporting, limit access to employees who genuinely need it, store the records in locked or encrypted systems, and cut off access when employees leave.13Federal Trade Commission. Protecting Personal Information – A Guide for Business
Business Deals
EINs change hands routinely during mergers, acquisitions, and other due diligence. Because the EIN identifies a company rather than a person, the privacy stakes are much lower.
Tax IDs in Court Filings
Court records are one place a tax ID can accidentally become visible. Federal Rule of Civil Procedure 5.2 addresses this directly: any filing containing a Social Security number or taxpayer identification number must include only the last four digits.14Legal Information Institute (LII). Rule 5.2 – Privacy Protection for Filings Made with the Court The rule was adopted under the E-Government Act of 2002 to address the privacy risk created by electronic access to court documents.
Parties and non-parties alike bear this responsibility. If you submit a document to a federal court, you are the one who has to redact. State courts have similar rules with varying specifics. If a full SSN slips into a filing, most courts will let you ask for the document to be sealed or replaced with a redacted version, but you have to catch it first.
Penalties for Unauthorized Disclosure
The consequences for improperly revealing someone’s tax information come from several directions at once.
Criminal Penalties
Unauthorized disclosure of tax return information, which includes the SSNs and ITINs attached to it, is a felony under Section 7213 of the Internal Revenue Code. A conviction can bring a fine of up to $5,000, imprisonment of up to five years, or both. Federal employees convicted under this provision face mandatory termination on top of the sentence.15Office of the Law Revision Counsel. 26 USC 7213 – Unauthorized Disclosure of Information
Civil Damages
You don’t need a prosecutor to act. Section 7431 lets you sue the United States (if a federal employee disclosed the information) or any other person who violated the confidentiality rules. Damages start at $1,000 per unauthorized act, even without proof of actual financial harm. If you can prove actual damages, you recover those instead, plus punitive damages if the disclosure was willful or grossly negligent, plus attorney’s fees.16Office of the Law Revision Counsel. 26 USC 7431 – Civil Damages for Unauthorized Inspection or Disclosure
Privacy Act Violations
For SSN disclosures, the Privacy Act adds a separate layer. A federal employee who willfully discloses records containing SSNs to unauthorized recipients commits a misdemeanor punishable by up to $5,000. The same penalty reaches anyone who obtains records from a federal agency under false pretenses.17Office of the Law Revision Counsel. 5 USC 552a – Records Maintained on Individuals
If Your Tax ID Is Misused
Tax ID theft happens despite the legal protections. If someone files a fraudulent return using your SSN or ITIN, the IRS will reject your legitimate return and you’ll spend weeks or months sorting it out. Two IRS tools help.
Form 14039
If you think someone is using your tax ID to file returns or claim refunds, submit Form 14039, the Identity Theft Affidavit. The fastest method is online submission at irs.gov. You can also fax it (toll-free to 855-807-5720 with a cover sheet marked “Confidential”) or mail it. If you are responding to an IRS notice about a suspicious return, send the form to the address on that notice. If you checked that someone filed using your SSN or ITIN, attach Form 14039 to the back of your paper return and mail them together.18Internal Revenue Service. Identity Theft Affidavit
Identity Protection PIN
The IRS also issues an Identity Protection PIN, a six-digit number that blocks anyone else from filing a return under your SSN or ITIN. Anyone with an SSN or ITIN can enroll, including parents requesting one for a dependent. The fastest route is your IRS online account.19Internal Revenue Service. Get an Identity Protection PIN
If you can’t verify your identity online and your adjusted gross income is below $84,000 ($168,000 for married filing jointly), you can submit Form 15227 and verify by phone instead. The IP PIN then arrives by mail in four to six weeks. As a last resort, you can book an in-person appointment at a Taxpayer Assistance Center. The IP PIN changes every year, so you’ll need to retrieve the new one from your online account each January.19Internal Revenue Service. Get an Identity Protection PIN