EIN Guide for a Maine Corporation — How to Get Your Federal Tax ID

An Employer Identification Number, or EIN, is a nine-digit number the IRS assigns to identify a business for federal tax purposes. It is sometimes called a Federal Tax Identification Number. Think of it as a Social Security number for your corporation — the identifier the government, banks, and payroll systems use to recognize the business as a distinct entity.

For a corporation, an EIN is not optional. Unlike a single-member LLC, which can sometimes use the owner's Social Security number, a corporation is always a separate taxpayer that files its own return. That means it must have its own federal tax ID from the start.

What you use the EIN for

• Filing the corporation's federal tax return — the C-corporation return, or the S-corporation return if you have elected that status
• Opening the corporate bank account — banks require the EIN to open an account in the corporation's name
• Running payroll — you need it to report and pay employment taxes if you hire employees
• Handling Maine tax registrations — the state ties your corporate tax and, where applicable, sales tax accounts to the EIN
• Establishing business credit and working with vendors who identify you by EIN rather than a personal SSN

Getting the EIN keeps your personal Social Security number off business paperwork and reinforces the separation between you and the corporation — separation that matters for your liability protection.

Timing matters. You should apply for the EIN after your corporation legally exists — that is, after the Maine Secretary of State has accepted your Articles of Incorporation — but before you try to open a bank account or hire anyone. Applying before the corporation is formed can create mismatches between the IRS record and the state record.

Have this ready before you apply

• Your corporation's exact legal name as it appears on the accepted Articles of Incorporation
• The state of incorporation (Maine) and the formation date
• The corporation's mailing address
• The responsible party — an individual who controls or manages the corporation, with their Social Security number or ITIN. The IRS wants a real person here, not another entity.
• The reason you are applying (starting a new business) and basic information about what the corporation does

Getting your legal name exactly right matters. If the name on the EIN application does not match the name on your Articles of Incorporation, you can run into problems later when a bank or the state cross-checks your records.

The IRS offers three ways to get an EIN, and which one you use depends mostly on whether the responsible party has a US Social Security number or ITIN.

Online (fastest, for those with an SSN or ITIN)

Apply through the IRS EIN Assistant at IRS.gov. The online application is the standard route. It takes about ten minutes, walks you through the questions, and issues the EIN immediately at the end — you can download and print the confirmation and use the number the same day. The application must be completed in one session, and the responsible party needs a valid SSN or ITIN. The service is free; there is no charge for an EIN directly from the IRS.

By fax

If you cannot or prefer not to use the online tool, you can fax a completed Form SS-4 to the IRS. Fax processing typically returns your EIN within a few business days if you include a return fax number.

By mail

Mailing Form SS-4 is the slowest option, often taking several weeks. It is mainly used by applicants who cannot apply online or by fax. If you are on any kind of timeline, avoid the mail route.

If you don't have an SSN or ITIN

The online EIN application requires the responsible party to have a US Social Security number or ITIN. If your responsible party has neither — common for international founders — you cannot use the online tool. Instead, you apply by fax or mail with Form SS-4, leaving the responsible party's tax ID field handled per the IRS instructions for foreign applicants. The EIN is still free; it just takes longer. Many foreign founders phone the IRS's international applicant line for guidance, since the process differs from the domestic online path.

Beware of paid EIN "services"

An EIN from the IRS is completely free. Some third-party websites charge a fee to "obtain" one for you and are designed to look official. You never have to pay the IRS for an EIN. If a filing service includes EIN acquisition as part of a broader package, that is a convenience fee for their time — but the number itself carries no government charge, and you can always get it yourself for free.

Common mistakes to avoid

• Applying before the corporation is formed, which can create a mismatch with the state record — form first, then apply.
• Getting the legal name wrong, even slightly, versus the Articles of Incorporation — banks and the state will cross-check.
• Listing an entity instead of a person as the responsible party — the IRS wants an individual who controls the corporation.
• Applying for multiple EINs for the same corporation by mistake — you need only one, and duplicates cause confusion. If something goes wrong mid-application, follow up rather than starting a second one.

Keep the EIN confirmation letter (the IRS calls it the CP 575) somewhere safe. Banks and agencies sometimes ask for it, and while you can request a replacement confirmation, having the original on hand saves time.