That distinction trips up many Australian founders setting up a US company. This guide covers how to get an EIN, how it connects to Form 2553 and Form 1120-S, which 2026 checks matter, and why shareholder eligibility needs review before you elect S status.
Key Takeaways
- An S corporation uses an EIN; there is no separate federal "S Corp tax ID."
- The EIN identifies the business, while Form 2553 elects S treatment.
- S corporations generally file Form 1120-S, not Form 1120.
- EIN alone does not create eligibility: nonresident-alien shareholders are barred.
What Is an S Corp Tax ID?
EIN, not a separate S corporation number
The IRS issues a nine-digit EIN for tax filing and reporting. Choosing S taxation does not require a corporation to get a new EIN, and Form 1120-S simply asks for the existing one.
Businesses commonly use the EIN for:
- Federal tax returns and information returns
- Payroll and employment tax filings
- Opening a business bank account
- Certain licence and account applications
EIN versus other identifiers
"Tax ID" is an umbrella term. The IRS taxpayer identification guidance explains that the SSA issues Social Security numbers, while the IRS issues EINs and ITINs. An EIN identifies a business; an ITIN serves certain individuals who cannot get an SSN.
State and local numbers are separate again. California's EDD, for example, issues its own eight-digit employer payroll tax account number. A business may need a sales tax account, a state employer account and an EIN, and one never substitutes for another.
S status is a tax election
An S corporation is a federal tax election made by an eligible corporation or LLC. The sequence runs like this:
- Form the entity with the state.
- Obtain an EIN.
- File Form 2553 to request S treatment.
An eligible LLC can file Form 2553 without a separate Form 8832 when the requirements are met.
When a new EIN is needed
A new charter or a new corporation formed after a statutory merger needs a new EIN. A corporate S election, name change or location change does not. Terminating an LLC and forming a new corporation is also a new-EIN event.
How to Get an EIN for an S Corp in 2026
Confirm entity details first
Before applying, settle the legal name, formation state, entity type, principal activity, tax year and responsible party. Match the legal name to your state formation records so it lines up with later filings.
Prepare the Form SS-4 information
The current Form SS-4 and instructions carry a December 2025 revision. You will typically need:
- Responsible party details
- Mailing and physical addresses
- Formation date
- Expected employee information, if relevant
- Reason for applying
The responsible party is the individual who ultimately owns or controls the entity. It is not your registered agent, tax preparer, nominee or service provider.
Choose the right application channel
The EIN is free from the IRS, and the IRS warns about websites that charge for it. The IRS online application requires a US business location and a responsible party with an SSN or ITIN. Most Australian founders without those must use another route:
| Route | Details |
|---|---|
| Telephone | +1 267-941-1099, Mon-Fri, 6 a.m.-11 p.m. US Eastern Time |
| Fax | 304-707-9471 from outside the US |
| Internal Revenue Service, Attn: EIN International Operation, Cincinnati, OH 45999 |
If the responsible party has no SSN or ITIN and is ineligible for one, line 7b allows "foreign" or "N/A".
Check the confirmation, then use it consistently
Check the notice for errors in the legal name, entity type, responsible party and address before using the number on Form 2553 or bank applications. Share it only with banks, payroll providers, tax professionals and agencies that need it, and keep files encrypted.
One entity should hold one EIN. Duplicate EINs or borrowing another entity's number cause tax, payroll and banking problems. The IRS also treats an unexpected duplicate-EIN filing rejection as a possible identity-theft warning sign.
How the EIN Connects to S Corp Election and Tax Filing
Form 2553 is the election
Form 2553 requests S treatment and includes the EIN as an identifier. The current version is dated December 2017, with instructions revised December 2020.
- Eligibility: a domestic corporation or eligible entity, 100 or fewer shareholders, one class of stock
- Deadline: generally 2 months and 15 days after the effective tax year begins
- Signatures: an authorised officer signs, and every shareholder consents. An unsigned form is not timely filed
- Late relief: Rev. Proc. 2013-30 generally allows relief within 3 years and 75 days of the intended effective date, if you show reasonable cause and consistent reporting
Form 1120-S versus Form 1120
An S corporation generally files Form 1120-S, an information return, rather than the C corporation's Form 1120. Each shareholder receives a Schedule K-1 and reports their share on a personal return.
For 2025, the Form 1120-S instructions set a due date of March 16, 2026. Form 7004 generally gives six months to file, but not extra time to pay.
Payroll and owner compensation
The EIN also drives payroll. Owner-employees receive wages, and the company generally files Form 941 quarterly, makes deposits and issues W-2s.
Payments for services must be treated as wages, and the IRS can reclassify distributions as wages. There is no fixed salary formula. Pay should be supportable given the owner's role, duties, industry and business facts.
State and local IDs stay separate
An EIN does not register you for state income tax, withholding, unemployment, sales tax or local licensing. State treatment of S elections also varies. New York City, for instance, has no city S election, and California charges 1.5% on S corporations with California-source income.
EIN confirmation is not S approval
The EIN notice (CP575, or Letter 147C for a previously assigned EIN) confirms the number. CP261 confirms the IRS accepted Form 2553, and the IRS says to keep it permanently. Store these together with:
- Form 2553 submission evidence
- State registrations and payroll records
- Governance documents
2026 Compliance Checks and Common Mistakes
Verify current forms and deadlines
Confirm current versions on IRS.gov before filing. The Form 941 instructions are dated March 2026, and the Form 7004 instructions are dated December 2025.
Calendar-year and fiscal-year entities have different deadlines. Weekends and federal holidays push the due date to the next business day, and state rules may differ.
Avoid common errors
- Applying under the wrong legal name
- Naming the wrong responsible party
- Filing Form 2553 without every shareholder consent or the officer signature
- Using another entity's EIN
- Assuming an EIN confirms S status
A quick pre-submission checklist:
- Legal name matches state records
- Responsible party is correct
- Every shareholder has signed
- All shareholders are eligible
- Shareholder count and stock class comply
Keep records and entity separation
Keep business and personal accounts apart. Maintain clear records for:
- Bookkeeping and payroll
- Shareholder records, distributions, and consent documentation
- On-time federal and state return filings
If your mailing address or responsible party changes, use Form 8822-B. Responsible-party changes are due within 60 days.
Special Considerations for Australian Founders and Businesses
Check shareholder eligibility first
IRC section 1361 prohibits nonresident-alien shareholders. A nonresident alien is someone who has passed neither the green card test nor the substantial presence test. Australian citizens and residents should get a US tax professional to determine their US classification before filing Form 2553.
An EIN does not fix this. Holding one proves nothing about eligibility.
An EIN does not change Australian obligations
A US EIN does not by itself change Australian tax residency, remove Australian reporting duties or decide where profits are taxed. Australian residents generally declare worldwide income, and foreign income can be attributed even if undistributed.
Points to review:
- Controlled foreign company rules and the ATO's supplementary return question on foreign entities
- Foreign income tax offsets, which need proof of payment
- The 1982 US-Australia treaty and 2001 protocol
The ATO has ruled that a qualifying single-member US LLC can be a foreign hybrid when it has not elected corporate treatment. That ruling does not establish how an S-elected entity is classified in Australia.
Coordinate US and Australian support
Get cross-border advice before forming the entity, electing S status, paying owners or moving funds between countries.
VJM Global, a chartered accountant firm that has served 250+ Australian businesses, offers accounting outsourcing and US tax-compliance support through US-compliant professionals. It cannot guarantee S corporation eligibility or IRS approval, but it can help coordinate the filings on both sides.
Frequently Asked Questions
How do I get an EIN number for an S corp?
Apply to the IRS using Form SS-4 or an eligible channel. Confirm your legal entity details and responsible party first. Applicants without a US location or SSN/ITIN use phone, fax or mail.
Is the tax ID the same as EIN?
For a business, usually yes. "Tax ID" is broader, though, and can also mean an SSN, ITIN or state tax account number.
Do S Corps use form 1120?
Generally no. S corporations file Form 1120-S. Confirm your actual tax classification against current IRS guidance.
Does an LLC have a tax ID or EIN?
An LLC can obtain an EIN when required or useful. An eligible LLC can also elect S treatment through Form 2553 without becoming a corporation under state law.
