Getting an EIN for a Massachusetts LLP

An Employer Identification Number is a nine-digit federal tax identifier issued by the Internal Revenue Service. It functions as the business equivalent of a Social Security number: it identifies your partnership on federal tax filings, on bank accounts, and in dealings with vendors and payers.

Why it is mandatory for an LLP

A single-member LLC can sometimes get by on the owner's Social Security number because the IRS treats it as a disregarded entity. An LLP cannot. By definition an LLP has two or more partners, and a partnership must file its own federal return — Form 1065 — and issue Schedule K-1s to the partners. A business that files its own return needs its own identifier, so the EIN is required from the start, regardless of whether the LLP has any employees.

Where the EIN comes from — and where it does not

The EIN is issued by the IRS, a federal agency. It has nothing to do with the Massachusetts Corporations Division or your LLP registration; those are separate, state-level matters. Getting an EIN does not register your LLP, and registering your LLP does not get you an EIN. They are two independent steps, and a complete setup needs both.

Timing matters a little. It usually makes sense to complete your Massachusetts LLP registration first, so the partnership legally exists, and then obtain the EIN for that registered entity. The IRS application asks for information about the business, and having your registered name and structure settled avoids inconsistencies between what the state shows and what the IRS has on file.

That said, the EIN comes before several downstream steps. You will need it to open the partnership's bank account, to set up payroll if you will have employees, and to file the partnership's tax returns. So the practical order is: register the LLP, get the EIN, then open the bank account and handle everything that depends on having both.

The IRS offers the EIN for free. You never need to pay a third party solely to obtain the number itself — the number is issued at no charge directly by the IRS.

Applying online

The fastest route is the online EIN application on the IRS website at IRS.gov. When the responsible party has a U.S. Social Security number or ITIN, the application is completed in one session and the EIN is issued immediately at the end, so you can begin using it the same day. The online tool is available during posted hours and must be finished in a single sitting; it does not save partway through.

The responsible party

The application asks for a "responsible party" — a person who controls or manages the partnership. For an LLP, this is typically one of the partners. The responsible party provides their Social Security number or ITIN to authenticate the application. Choose a partner who genuinely has authority, because the responsible party is the individual the IRS associates with the entity.

Applying without an SSN or ITIN

If the responsible party does not have a Social Security number or ITIN, the online tool will not work. In that case the application is submitted on Form SS-4 by fax or mail, which takes longer than the immediate online issuance. International partners setting up a Massachusetts LLP often fall into this path.

What you will need on hand

• The LLP's exact legal name as registered in Massachusetts
• The partnership's principal business address
• The responsible party's name and taxpayer identification number
• The type of entity (a partnership) and the reason for applying
• The number of partners and a general description of the business

Once issued, the EIN follows the partnership for the rest of its life and shows up across your business operations.

Opening the bank account

Banks require the EIN to open a partnership account, along with your accepted Massachusetts LLP registration and typically the partnership agreement. Keeping partnership funds in an account under the LLP's own EIN — separate from any partner's personal accounts — is part of operating the entity credibly and keeping the partnership's finances distinct from the partners' personal finances.

Filing partnership taxes

The EIN is the number on the partnership's federal Form 1065 and on the Schedule K-1s issued to the partners. It is also the identifier the LLP uses for Massachusetts Department of Revenue partnership filings. Every tax touchpoint for the entity runs through the EIN.

Payroll and vendors

If the LLP hires employees, the EIN is used for federal payroll tax deposits and employment tax returns. Vendors and clients that need to issue the partnership a 1099, or that request a W-9, will use the EIN as well.

Getting the EIN is a straightforward federal step, and many partnerships obtain it directly from the IRS at no cost after their Massachusetts LLP registration is complete. What Mainstay Filing focuses on is the state side — preparing and filing your LLP registration with the Corporations Division correctly, so that when you apply for the EIN the entity name and structure the IRS records line up cleanly with what Massachusetts shows.

Getting the sequence and the details consistent between the state registration and the federal EIN saves you from mismatches that can complicate bank onboarding and tax filing later. We make sure the Massachusetts foundation is solid; the free federal number then slots in on top of it.

Keep the confirmation somewhere safe

When the IRS issues the EIN, you receive a confirmation notice — the CP 575 for online applicants. Save it. Banks may ask to see it when you open the partnership account, and it is the cleanest proof of the number if a question ever arises. Store it with your accepted LLP registration and your partnership agreement so the three documents that define your Massachusetts LLP — state registration, federal EIN, and internal governing agreement — live together and are easy to produce when a bank, a lender, or a large client asks for them.