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).

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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@2.0.0.

Registry entry

us/irs/employer-identification-number-ss4

Jurisdiction
United States · national
Version
2.0.0
Verification
draft
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-ss4/2.0.0/schema.jsonapplication/schema+json
Verification record
registry/us/irs/employer-identification-number-ss4/2.0.0/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 person signing the application under penalties of perjury, and their title (e.g. "Sole Proprietor", "Managing Member", "Trustee").

    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's own VERIFICATION.md stays as the authoring provenance for that version and is not edited (VERSIONING.md §3 immutability); this is a fresh record for v2.0.0, not a correction of v1.0.0.

Current claim

  • status: draft (unchanged from v1.0.0 — this version does not perform the independent field-by-field re-review; see "What is NOT yet independently verified" below)
  • verification.method: manual-source-review-v1
  • verification.lastVerifiedAt: 2026-07-01

Why this is a MAJOR version, not a MINOR/PATCH

Per GOV-319 (RFC 0003 §8, flagship plan point 1), this version is a structural modeling upgrade, not a content correction: it converts prose "required only when..." rules into real requiredWhen conditions (GSP-0013 §2) and expresses the online-vs-fax/mail/phone eligibility gate as a real steps[].transitions branch with exitReason (GSP-0013 §4), now that spec/v0.3 (GOV-373) exists.

Two new required fields were added — principalBusinessInUS and responsiblePartyHasSSNITIN — to make the eligibility gate mechanically evaluable (see below). A new required field invalidates any v1.0.0 data that lacks it, so per VERSIONING.md §5.3 this is a MAJOR bump (1.0.0 → 2.0.0), not additive.

Sources examined

  • Document (id, version): us/irs/employer-identification-number-ss4 / 2.0.0
  • Spec version: GovSchema 0.3.0
  • Primary source URL: https://www.irs.gov/forms-pubs/about-form-ss-4 (unchanged from v1.0.0; the Form SS-4 line 1–18 field set itself is untouched by this version)
  • Online-application eligibility rule (re-confirmed live for this version): https://www.irs.gov/businesses/small-businesses-self-employed/apply-for-an-employer-identification-number-ein-online, "Who can use this tool" section, fetched 2026-07-01: > Use this if: Your principal place of business is in the U.S. or U.S. > territories. You're the responsible party in control of the entity or its > authorized representative. You have the responsible party's Social > Security or individual taxpayer ID number (ITIN). > You can't use this: If your principal place of business is outside the > U.S. Apply by phone, fax or mail. To apply with an EIN. Only government > entities may apply with an EIN.
  • Retrieved / reviewed: 2026-07-01
  • Reviewer: GovSchema Engineering (Standards Engineer)

What changed from v1.0.0

  • Two new fields, principalBusinessInUS and responsiblePartyHasSSNITIN (fieldRole: eligibility, GSP-0014 §2), sourced from the online-assistant eligibility page quoted above — not Form SS-4 line items themselves, which is why each carries a sourceRef naming the online assistant page rather than a line number.
  • New first step eligibility_check, carrying those two fields and a transitions array (not next) with two to: null exits — principal-business-outside-us-apply-by-fax-mail-or-phone and responsible-party-lacks-ssn-itin-apply-by-fax-or-mail — and a fallthrough into the existing entity_identification step. This document still models the Form SS-4 field set common to every channel (per v1.0.0's own scope note); the to: null exits mark "online assistant not usable, the applicant needs the fax/mail/phone channel instead" as recorded in the form instructions' "How To Apply" section, not "stop collecting data" — an ineligible-for-online applicant still completes the same lines 1–18 on paper.
  • requiredWhen added to 11 fields whose description already stated a conditional-requiredness rule in prose: llcMemberCount/llcOrganizedInUS (isLLC: true), entityTypeOtherSpecify (entityType in other_nonprofit_organization/other), entityTypeCorporationFormNumber (entityType: corporation), entityTypeTrustGrantorTin (entityType: trust), entityTypeEstateDecedentSSN (entityType: estate), entityTypePlanAdministratorTin (entityType: plan_administrator), reasonForApplyingSpecify (6-way reasonForApplying branch), expectedAgriculturalEmployees/expectedHouseholdEmployees/ expectedOtherEmployees (highestExpectedEmployees > 0), and previousEIN (previouslyAppliedForEIN: true). The existing prose in each field's description is left in place — it remains accurate human-facing text, now backed by a machine-checkable rule instead of being the rule's only home.
  • visibleWhen added to incorporationState/incorporationForeignCountry (entityType: corporation). Not requiredWhen: the source further splits these two on whether the corporation was incorporated in vs. outside the U.S., and no field in this document captures that sub-fact, so asserting an exact requiredWhen for either would overclaim a condition this document cannot actually evaluate. visibleWhen narrows correctly (both are irrelevant outside entityType: corporation) without overclaiming requiredness the schema can't verify.
  • crossFieldValidation added, one rule (employmentCountsRequireHighestCount): when highestExpectedEmployees is 0, expectedAgriculturalEmployees, expectedHouseholdEmployees, and expectedOtherEmployees MUST be absent — the same rule GSP-0013 §3 used this exact field set to motivate.
  • Two fields intentionally NOT converted, to avoid overclaiming a condition the Condition grammar cannot express: thirdPartyDesigneePhone/ thirdPartyDesigneeAddressAndZip are "required only when thirdPartyDesigneeName is given" — a presence check, not an equality check, and GSP-0013's grammar has no isPresent/isAbsent operator (leaf comparisons are equals/notEquals/in/ordering against a literal or another field's value, never "is set"). Left as prose-only, same as v1.0.0, rather than forcing an approximate equals/notEquals against a placeholder value the source doesn't actually define.

What is NOT yet independently verified

Unchanged from v1.0.0 (see that version's VERIFICATION.md): the full "Do I Need an EIN?" line-subset table, the online assistant's actual screen-by-screen interview, and constraint patterns remain as documented there. This version adds structural modeling of already-known facts; it does not perform the field-by-field independent re-review that would advance status to verified.

Re-verification

Per the practice's cadence, nextReviewBy for this record follows the same 2026-07-01 review date as v1.0.0's cadence reset: 2027-01-01. Re-check both the Form SS-4 source and the online-assistant eligibility page on or before that date.

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.