EIN Guide for a New Mexico LLP

An Employer Identification Number is a nine-digit federal tax ID the IRS assigns to a business. Think of it as the business equivalent of a Social Security number — it identifies the partnership on federal tax filings, on bank paperwork, and to government agencies.

Why an LLP is different from a single-member LLC

A single-member LLC can sometimes get by using the owner's Social Security number, because the IRS treats it as a disregarded entity. A limited liability partnership cannot. By definition an LLP has at least two partners, so the IRS treats it as a partnership for federal tax purposes. Partnerships must file their own information return — Form 1065 — and issue Schedule K-1s to the partners. Filing that return requires an EIN. There is no version of a New Mexico LLP that skips the EIN; it is a fundamental requirement of the structure.

What you use the EIN for

• Filing the partnership's federal return and issuing K-1s
• Opening a business bank account (banks require it)
• Hiring employees and running payroll
• Registering for New Mexico's Gross Receipts Tax
• Applying for business credit and certain licenses

The right time to apply for an EIN is after your Statement of Qualification is filed and the LLP officially exists, but before you try to open a bank account or register for state taxes.

The reason to wait until after registration is that the EIN application asks for the partnership's legal name and details, and you want those to match exactly what is on file with the New Mexico Secretary of State. Applying before the LLP is registered risks a mismatch — an EIN tied to a name or structure that does not match your state record, which causes friction at the bank and with the state later.

The reason not to wait too long is that almost everything else depends on the EIN. You cannot open the partnership's bank account without it, and you cannot register for Gross Receipts Tax without it. So the sequence is clean: register the LLP, get the EIN, then open accounts and register for taxes.

The IRS issues EINs at no cost. Be wary of any site that charges a "fee" to obtain an EIN — the number itself is always free directly from the IRS. Applying through Mainstay Filing as part of a formation package simply means we handle the application on your behalf; the IRS still charges nothing for the number.

Applying online

The fastest route is the IRS EIN Assistant at IRS.gov. The online application:

• Takes about ten minutes to complete
• Issues the EIN immediately upon completion, so you can print the confirmation and use the number the same day
• Is available during the IRS's posted hours for the assistant
• Requires a responsible party with a valid U.S. Social Security number or ITIN

Applying by fax or mail

If the partnership's responsible party does not have an SSN or ITIN — common for partnerships with foreign partners — you apply using Form SS-4 submitted by fax or mail. This takes longer than the online route, so plan for the extra time if it applies to you.

The responsible party

The IRS requires you to name a responsible party: a real person who controls or manages the partnership, not the entity itself. For an LLP, this is typically one of the partners. The responsible party's information goes on the application, so decide who it will be before you start.

Gathering a few details first makes the application quick and error-free.

Information you'll need

• The partnership's exact legal name as filed with the New Mexico Secretary of State, including the LLP designator
• The principal office address
• The responsible party's name and SSN or ITIN
• The date the LLP was registered (the effective date of the Statement of Qualification)
• The number of partners and the general nature of the business
• The reason for applying — typically "started a new business"

Match your state record

The most important thing is consistency. The name and structure you put on the EIN application should match your New Mexico registration exactly. A partnership registered as "Rivera & Chen Consulting LLP" should apply for its EIN under that exact name. Mismatches between the IRS record and the state record cause problems at the bank and complicate future filings, and they are annoying to fix after the fact.

Once the EIN is issued, keep the confirmation letter (the IRS calls it the CP 575) somewhere safe — banks and agencies ask for it, and the IRS does not casually reissue it. Then the EIN unlocks the next steps.

Opening the bank account

Take the filed Statement of Qualification, the EIN confirmation, your partnership agreement, and ID for the authorized partners to the bank. Keeping partnership finances entirely separate from any partner's personal accounts is essential — both for clean books and to preserve the integrity of the liability shield.

Registering for New Mexico Gross Receipts Tax

If the LLP sells goods or provides taxable services in New Mexico, use the EIN to register for a Gross Receipts Tax account with the Taxation and Revenue Department. The EIN is how the state ties the tax account to the partnership.

Payroll, if you hire

If the partnership hires employees, the EIN is the number payroll and employment tax filings run through. You will also handle state employer registrations at that point.

How Mainstay Filing helps

When EIN service is part of your formation package, we prepare and submit the application so the details line up with your New Mexico registration, and we deliver the confirmation to you. It removes one more thing to figure out while you are getting the partnership off the ground.