Registry entry

United States Employer Identification Number Application (Form SS-4)

Apply for an Employer Identification Number (EIN), the 9-digit federal tax identifier the IRS assigns to a business entity, using the data model of IRS Form SS-4 (Application for Employer Identification Number). Covers a single-member LLC, sole proprietorship, corporation, partnership, trust, estate, or nonprofit applying for its first EIN. The fastest channel is the IRS EIN online assistant (immediate issuance), available only to applicants whose principal business is in the U.S. or a U.S. territory and whose responsible party has an SSN or ITIN; applicants outside that scope must apply by fax, mail, or (international applicants only) telephone, using this same Form SS-4 field set. It does not submit the application; the live IRS source is always authoritative (see VERIFICATION.md).

You are viewing v2.2.0

The latest published version of this schema is v2.3.0 — see the current reference page. Published versions are immutable; this page stays for agents pinned to us/irs/employer-identification-number-ss4@2.2.0.

Registry entry

us/irs/employer-identification-number-ss4

Jurisdiction
United States · national
Version
2.2.0
Verification
verified
Authority
Internal Revenue Service

GovSchema spec v0.3

Authoritative source Form SS-4 (Rev. December 2025)

Machine access

Schema document
registry/us/irs/employer-identification-number-ss4/2.2.0/schema.jsonapplication/schema+json
Verification record
registry/us/irs/employer-identification-number-ss4/2.2.0/VERIFICATION.mdtext/markdown
Registry catalog
registry/index.jsonone record per schema id

Field reference

51 fields across 12 steps, read from the published schema.json — names, types, requiredness, and validation as the document states them. The live government form remains the authoritative source.

Online-application eligibility check

  • principalBusinessInUS boolean required

    Online EIN assistant eligibility gate (not itself a Form SS-4 line item). The online assistant is limited to applicants whose principal place of business is in the U.S. or U.S. territories; if false, apply by fax, mail, or (international applicants only) telephone instead, using this same field set.

  • responsiblePartyHasSSNITIN boolean required

    Online EIN assistant eligibility gate (not itself a Form SS-4 line item). The online assistant is limited to responsible parties identified by SSN or ITIN, not an EIN; if false, apply by fax or mail instead. See responsiblePartyTaxId for the actual identifier.

Entity name

  • entityLegalName string required

    Personal/business identifier; handle as sensitive data. The legal name of the business, trust, estate, or individual applying — e.g. as it appears on the entity's formation document, or an individual's legal name for a sole proprietorship.

    length: 1–160
  • tradeName string optional

    The 'doing business as' (DBA) name, if different from the legal name.

    length: 0–160
  • careOfName string optional

    Personal identifier; handle as sensitive data. Required when the applicant entity is an estate or trust and correspondence should be directed to a named executor, administrator, or trustee.

    length: 0–160

Mailing and principal addresses

  • mailingAddressLine1 string required

    Where the IRS will send the EIN confirmation notice (CP 575) and correspondence. A P.O. box is allowed here, unlike the principal (street) address.

    length: 1–120
  • mailingAddressCity string required

    If foreign, the instructions give a different city/province/postal-code format; see mailingAddressCountry.

    length: 1–80
  • mailingAddressState string optional

    Two-letter USPS state or territory abbreviation, e.g. CA, NY, TX. Not applicable to a foreign address; see mailingAddressCountry instead.

    pattern
  • mailingAddressPostalCode string optional

    5-digit or ZIP+4 U.S. format, e.g. 90210 or 90210-1234. For a foreign address, give the foreign postal code here instead, per the instructions.

    length: 0–15
  • mailingAddressCountry string optional

    Required only when the mailing address is outside the United States; see the Form SS-4 instructions for the foreign address format.

    length: 0–100
  • principalAddressLine1 string optional

    The entity's actual physical/principal business location. Cannot be a P.O. box, unlike the mailing address.

    length: 0–120
  • principalAddressCity string optional

    Required only when principalAddressLine1 is given.

    length: 0–80
  • principalAddressState string optional

    Two-letter USPS state or territory abbreviation. Required only when principalAddressLine1 is a U.S. address.

    pattern
  • principalAddressPostalCode string optional

    Required only when principalAddressLine1 is given.

    length: 0–15
  • principalBusinessCountyAndState string optional

    Free-text county name and state, e.g. "Orange County, CA". Not applicable to every reason for applying (e.g. not needed for a banking-purpose-only application); see reasonForApplying.

    length: 0–120

Responsible party

  • responsiblePartyName string required

    Personal identifier; handle as sensitive data. The person who ultimately owns or controls the entity, or who exercises ultimate effective control. Per the Form SS-4 instructions, the responsible party must be an individual (a natural person), not an entity, except where the applicant itself is a government entity. Required on every EIN application regardless of reason for applying.

    length: 1–160
  • responsiblePartyTaxId string required

    Personal identifier; handle as sensitive data. 9 digits, no separators. The IRS online EIN assistant additionally requires this to be an SSN or ITIN (not an EIN) and requires the responsible party themselves to be the applicant or their authorized representative.

    pattern

Limited liability company details

  • isLLC boolean optional

    Required for most applicants, but not on every path: the Form SS-4 "Do I Need an EIN?" table (page 2) excludes line 8a from the lines to complete for a plan administrator, an estate administrator, or a state/local tax-reporting agency. If true, also give llcMemberCount and llcOrganizedInUS, and see the instructions for the correct entityType box.

  • llcMemberCount integer optional

    Required only when isLLC is true.

    range: 1–∞
  • llcOrganizedInUS boolean optional

    Required only when isLLC is true.

Type of entity

  • entityType enum required

    Check only one box. If isLLC is true, see the instructions for which box applies to the LLC (an LLC is not itself a box; it is classified as one of these types for tax purposes).

    enum: 16 values
  • entityTypeOtherSpecify string optional

    Required only when entityType is other_nonprofit_organization or other.

    length: 0–160
  • entityTypeCorporationFormNumber string optional

    Required only when entityType is corporation, e.g. 1120 or 1120-S.

    length: 0–20
  • entityTypeTrustGrantorTin string optional

    Personal identifier; handle as sensitive data. Required only when entityType is trust.

    pattern
  • entityTypeEstateDecedentSSN string optional

    Personal identifier; handle as sensitive data. Required only when entityType is estate.

    pattern
  • entityTypePlanAdministratorTin string optional

    Personal identifier; handle as sensitive data. Required only when entityType is plan_administrator.

    pattern
  • groupExemptionNumber string optional

    Applies only to certain nonprofit/church-affiliated group-ruling entities.

    length: 0–10
  • incorporationState string optional

    Two-letter USPS state abbreviation. Required only when entityType is corporation and the corporation was incorporated in the U.S.; use incorporationForeignCountry instead for a foreign incorporation.

    pattern
  • incorporationForeignCountry string optional

    Required only when entityType is corporation and the corporation was incorporated outside the U.S.

    length: 0–100

Reason for applying

  • reasonForApplying enum required

    Check only one box.

    enum: 9 values
  • reasonForApplyingSpecify string optional

    Required when reasonForApplying is started_new_business (type of business), changed_type_of_organization (new type), created_a_trust (type of trust), created_a_pension_plan (type of plan), banking_purpose (purpose), or other.

    length: 0–200

Business start date, accounting year, and employees

  • businessStartDate date optional

    YYYY-MM-DD. Not required on every reason-for-applying path (e.g. not needed for a banking-purpose-only application); see the Form SS-4 instructions for line 11.

  • accountingYearClosingMonth enum optional

    The last month of the entity's accounting year (December for a calendar-year filer). Not required on every reason-for-applying path.

    enum: 12 values
  • highestExpectedEmployees integer optional

    If 0, expectedAgriculturalEmployees, expectedHouseholdEmployees, and expectedOtherEmployees, along with line 14/15, may be left unanswered.

    range: 0–∞
  • expectedAgriculturalEmployees integer optional

    Only completed when highestExpectedEmployees is greater than 0.

    range: 0–∞
  • expectedHouseholdEmployees integer optional

    Only completed when highestExpectedEmployees is greater than 0.

    range: 0–∞
  • expectedOtherEmployees integer optional

    Only completed when highestExpectedEmployees is greater than 0.

    range: 0–∞
  • file944AnnuallyElection boolean optional

    Available only if expected employment tax liability is $1,000 or less in a full calendar year (generally, $5,000 or less in total wages, or $6,536 or less in a U.S. territory). If not checked, the entity must file Form 941 quarterly.

  • firstWagesPaidDate date optional

    YYYY-MM-DD. If the applicant is a withholding agent, this is instead the date income will first be paid to a nonresident alien. Only applicable when employees are expected (highestExpectedEmployees greater than 0) or the entity is a withholding agent.

Principal business activity

  • principalActivity enum optional

    Check one box that best describes the principal activity. Not required on every reason-for-applying path.

    enum: 12 values
  • principalActivityOtherSpecify string optional

    Required only when principalActivity is other.

    length: 0–160
  • principalLineOfBusiness string optional

    Free text, e.g. "Residential electrical contracting".

    length: 0–200

Previous EIN

  • previouslyAppliedForEIN boolean required

    A new EIN is generally not issued to the same legal entity twice; see the instructions if unsure whether the entity already has one.

  • previousEIN string optional

    Required only when previouslyAppliedForEIN is true. Format NN-NNNNNNN.

    pattern

Third party designee (optional)

  • thirdPartyDesigneeName string optional

    Personal identifier; handle as sensitive data. Complete this section only to authorize a named individual to receive the entity's EIN and answer questions about this application; the designee's authority terminates once the EIN is assigned and released.

    length: 0–160
  • thirdPartyDesigneePhone string optional

    Required only when thirdPartyDesigneeName is given. In international E.164 format, e.g. +12025551234.

    pattern
  • thirdPartyDesigneeAddressAndZip string optional

    Required only when thirdPartyDesigneeName is given.

    length: 0–200
  • thirdPartyDesigneeFax string optional

    In international E.164 format, e.g. +12025551234.

    pattern

Signature

  • applicantNameAndTitle string required

    Personal identifier; handle as sensitive data. The name and title (e.g. "Sole Proprietor", "Managing Member", "Trustee") of the person signing the application. See the applicantSignature attestation entry in documents[] for the perjury statement they are certifying to.

    length: 1–160
  • applicantPhone string required

    Personal identifier; handle as sensitive data. In international E.164 format, e.g. +12025551234. The IRS online EIN assistant may use this number to contact the applicant about the application.

    pattern
  • applicantFax string optional

    In international E.164 format, e.g. +12025551234.

    pattern

Verification record

This file is the source-review record for this document version, per the manual-source-review-v1 practice. v1.0.0/v2.0.0/v2.1.0's own VERIFICATION.md files stay as the authoring provenance for those versions and are not edited (VERSIONING.md §3 immutability); this is a fresh record for v2.2.0.

Current claim

  • status: verified (advanced from draft — this version performs the full independent field-by-field re-review the practice requires; see "Independent second-reviewer pass" below)
  • verification.method: manual-source-review-v1
  • verification.lastVerifiedAt: 2026-07-01
  • maturity.level: agent-ready-schema (new — see "Maturity declaration" below)

This closes out GOV-404 (split from GOV-319, RFC 0003 §8 deliverable 3 of 5).

Why this is a MINOR version, not PATCH or MAJOR

Two independent changes are bundled in this release:

  1. A label fix (principalAddressLine1, see below) and a verification refresh (status: draft → verified, lastVerifiedAt refreshed). Per VERSIONING.md §1 and its "Status interaction" note, either of these alone is a PATCH: no change to the data contract, "re-verify against the live source with no field changes" and "fix label... or other annotations."
  2. The maturity top-level member, added for the first time on this document (GSP-0012, folded into spec/v0.3). This is the first schema in the registry to declare maturity — no prior-version precedent exists for its own bump size, so this record sets one: maturity is a new OPTIONAL, additive top-level member, the same category v2.1.0's own record placed documents[] in ("a new OPTIONAL field... a new step that does not alter existing required inputs" — VERSIONING.md §5.3-referenced MINOR rule). Any 2.1.0-conforming applicant data remains valid under 2.2.0; a consumer simply gains one more structured fact (the maturity badge) to act on. That makes the maturity addition MINOR-tier, which is the higher of the two bundled changes, so the release as a whole bumps 2.1.0 → 2.2.0 (MINOR), not a PATCH.

Independent second-reviewer pass

Per the practice's Procedure steps 2–3, and per GOV-404's explicit instruction that this be "a genuine independent second-reviewer pass — not the same reviewer re-asserting the original authoring claim":

  • Source re-fetched fresh, not assumed from prior records: the live Form SS-4 PDF (https://www.irs.gov/pub/irs-pdf/fss4.pdf), the "About Form SS-4" page, the EIN online-application eligibility page, and the Form SS-4 instructions ("How To Apply" section), all retrieved 2026-07-01.
  • A different, higher-fidelity extraction method than prior versions used. v1.0.0/v2.0.0/v2.1.0's records describe decoding the PDF's content streams and reading Tj/TJ text-showing operators. Re-attempting that exact technique this pass found zero literal Tj/TJ operators anywhere in the decompressed streams — Form SS-4 is an XFA-dynamic PDF (its decompressed streams are dominated by XFA template XML: caption, exData, textEdit, field name="f1_41", etc., not page content-stream text-showing operators), so that described technique could not actually have recovered the field labels the way its own prose claims. This pass instead used pdfjs-dist's page getTextContent() (reads the true rendered page text, regardless of the PDF's internal AcroForm/XFA structure) plus getAnnotations() (to confirm the AcroForm field/widget layout matches the visible line numbering). This is a methodology-provenance correction, not a content defect: independently re-deriving the full page text this way and diffing it field-by-field against schema.json confirmed the previously-recorded field content itself was accurate (see below) — the prior records' description of how they got that content does not hold up to a literal repeat, but what they recorded checks out.
  • Full field-by-field comparison, all 40 fields[] entries plus the two eligibility-gate fields, against the freshly-extracted Form SS-4 line text (lines 1–18, Third Party Designee, and signature block) and the online eligibility page: every label, type, required, validation (all three enum lists — entityType's 16 options, reasonForApplying's 9, principalActivity's 12 — recounted and matched exactly, including the wholesale_agent_broker/wholesale_other distinction), and sourceRef was checked. One discrepancy found (below); every other entry matched.
  • Flow comparison (Procedure step 3): the steps[] ordering and field grouping match the form's line ordering and section breaks (Third Party Designee, signature block). The eligibility_check step's two to: null exits still match the live online-assistant eligibility page's "Who can use this tool" / "You can't use this" wording, re-confirmed verbatim this pass.
  • documents[].applicantSignature.statement re-confirmed verbatim against the freshly-extracted signature-block text: unchanged, exact match.
  • Cross-checked supporting facts used in field descriptions, re-fetched live rather than trusted from prior records: the designee's-authority- terminates-at-EIN-issuance note ("The designee's authority terminates at the time the EIN is assigned and released to the designee." — instructions' Third Party Designee section) and the responsible-party-must-be-an- individual rule with its government-entity exception ("Unless the applicant is a government entity, the responsible party must be an individual... If you are applying for an EIN for a government entity, you may enter an EIN for the responsible party on line 7b.") — both still accurate as described.
  • Source currency re-confirmed: the "About Form SS-4" page and the PDF's own header/footer both still read "Rev. December 2025" / "Rev. 12-2025" — no new revision since v1.0.0 first authored this document.

Discrepancy found and corrected

  • principalAddressLine1 label. The live form's line 5a caption reads "Street address (if different) (Don't enter a P.O. box.)" The prior label, "Street address (if different from mailing address)", paraphrased the first clause and silently dropped the second — the "don't enter a P.O. box" instruction was present only in the field's description ("Cannot be a P.O. box, unlike the mailing address"), not in label itself, which the practice's Procedure step 2 requires to "match the source wording." Corrected to "Street address (if different) (don't enter a P.O. box)". No type/required/validation/sourceRef change — this is a label-only fix.

Documentation-only correction (does not touch schema.json)

  • "Nine" applicant situations, corrected to thirteen. v1.0.0's "Corrections from independent review" section (carried forward by reference in every later version's "What is NOT yet independently verified") describes the Form SS-4 page 2 "Do I Need an EIN?" table as covering "nine different applicant situations." A fresh, full read of that table this pass counts 13 distinct IF the applicant... rows (started a new business; hired employees; opened a bank account; changed type of organization; purchased a going business; created a trust; created a pension plan as a plan administrator; is a foreign person needing an EIN to comply with IRS withholding regulations; is administering an estate; is a withholding agent for nonwage income paid to an alien; is a state or local agency; is a single-member LLC; is an S corporation) — the "nine" in the older records conflates the row count with the table's nine numbered footnotes, which is a different thing. This is a correction to verification-record prose only; schema.json itself never states a situation count. The earlier records are immutable and are not edited (VERSIONING.md §3); this record states the corrected count for any future reviewer.
  • Substantively, the flat required model still holds against all 13 rows, re-checked individually. Every field this document marks required: true at the top level (entityLegalName, mailingAddressLine1, mailingAddressCity, responsiblePartyName, responsiblePartyTaxId, entityType, reasonForApplying, previouslyAppliedForEIN) falls inside every one of the 13 rows' "complete lines..." ranges — none of the 13 situations excludes any of them. And isLLC's required: false (the correction v1.0.0 already made) is confirmed exactly right: line 8a is excluded from the required-lines list for exactly 3 of the 13 rows — plan administrator, estate administrator, and state/local tax-reporting agency — matching v1.0.0's finding precisely, just against the corrected denominator (3 of 13, not 3 of 9). No required flag needed to change.

Maturity declaration

Per GSP-0012 and maturity-self-assessment-v1, applying that practice's Procedure:

  1. Structural Reference — true. fields[] is present, every entry carries type, and exactly one source is cited.
  2. Verified Schema — true, as of this version: status: verified with verification.lastVerifiedAt: 2026-07-01, current per the practice's 6-month cadence (nextReviewBy: 2027-01-01).
  3. Agent-Ready Schema — true. Re-checked against the live source (not just the document's own shape) per the practice's step 3 instruction to re-read the source alongside the document:
    • The one real branch in the source process — the online-assistant eligibility gate — is expressed as steps[].transitions with real Conditions (GSP-0013), not left in prose. The "Do I Need an EIN?" table is not a branch with an exit: every one of its 13 rows concludes with completing and submitting Form SS-4 by some channel; none of them is a "don't apply" outcome. It varies which lines are required, which the flat required/requiredWhen model already captures (re-confirmed above) — there is no additional steps[].transitions branch this document is missing.
    • The one real attestation requirement (the perjury signature) is expressed in documents[]; the one real eligibility requirement (online-assistant access) is expressed via fieldRole: eligibility on principalBusinessInUS/responsiblePartyHasSSNITIN (GSP-0014). There is no payment requirement to model — Form SS-4 has no application fee — and no file-upload/identity-document requirement, both re-confirmed this pass (no fee is mentioned anywhere in the form, its instructions, or the online-assistant page).
    • Both terminal/exit states the source defines (ineligible for the online assistant on either eligibility-gate condition) are reachable via explicit to: null transitions with exitReason; neither is silently absent.
  4. Execution-Tested Schema — false, and out of scope for this issue. 2.1.0/mapping.json and conformance/.../2.1.0/browser-flow.json exist but are pinned to schema.version: "2.1.0" (SPEC §17 referential integrity) and were not carried forward to 2.2.0 — GOV-404 scopes this re-verification to the Agent-Ready tier only, not Execution-Tested. Advancing to execution-tested-schema would require authoring a 2.2.0-pinned mapping.json and conformance fixture as separate, follow-on work; tracked as a future issue if desired, not implied by this record.

Per the ladder rule (GSP-0012 §2, SPEC §10), criteria.agentReadySchema: true with every lower tier also true and executionTestedSchema: false derives maturity.level: "agent-ready-schema", matching the meta-schema's oneOf constraint.

Sources examined

Re-verification

Per the practice's Cadence, nextReviewBy is 2027-01-01 (6 months). Re-check the Form SS-4 PDF, the "About Form SS-4" page, the online-assistant eligibility page, and the instructions' "How To Apply" section on or before that date, or sooner if the IRS publishes a new Form SS-4 revision.

View the raw record (VERIFICATION.md)

Version history

Independent and non-affiliated

GovSchema is an independent, open-source project. This reference is not produced, reviewed, or endorsed by Internal Revenue Service or any government. The authoritative source is always the live government form and its official instructions.