Getting an EIN for Your Wisconsin LLP

An Employer Identification Number is the nine-digit number the IRS issues to identify a business for federal tax purposes. Think of it as a Social Security number for a business — it's how the federal government identifies your partnership on tax filings, and how banks and payroll systems identify the firm.

For a limited liability partnership, an EIN isn't a nice-to-have; it's a practical necessity. A partnership with two or more partners is treated as a partnership for federal tax purposes, and a partnership files its own return — it cannot operate on a single partner's Social Security number the way a solo sole proprietor sometimes can. The EIN is what the firm uses to file that return and to identify itself to banks, the state, and any employees.

Where the EIN fits with your Wisconsin registration

Your EIN is a federal identifier from the IRS, entirely separate from your state registration with the Wisconsin Department of Financial Institutions. The DFI registers the LLP as an entity in Wisconsin; the IRS assigns the EIN for federal tax purposes. You'll typically register the LLP with the DFI first, then obtain the EIN — most people get the EIN right after the registration is accepted, because the bank account and tax setup depend on it.

For most LLPs the answer is simple: right away. But it's worth being precise about the specific triggers, because each one on its own requires an EIN.

The clear triggers

• Multiple partners. A multi-partner LLP files a federal partnership return (Form 1065) and issues Schedule K-1s to the partners. That return requires an EIN — there's no way around it.
• Opening a business bank account. Banks require an EIN to open a partnership account. Keeping the firm's money separate from the partners' personal money is essential to preserving the liability shield, and a proper bank account requires the EIN.
• Hiring employees. If the firm will pay employees, it needs an EIN to handle federal payroll tax, withholding, and employment tax filings.
• Certain tax elections and accounts. Setting up state tax accounts and making certain federal elections rely on having an EIN.

For a partnership, essentially all of these apply, which is why the practical guidance is to get the EIN as soon as the DFI accepts your registration. There's no reason to wait — the application is free and immediate.

The IRS issues EINs directly, and applying online is the fastest route. Do not pay a large fee to a third party for the EIN itself — the IRS charges nothing.

Applying online

• Go to the IRS EIN Assistant at IRS.gov.
• Select the partnership entity type, since a multi-partner LLP is taxed as a partnership.
• Provide the firm's legal name (as registered with the DFI), its address, and the responsible party's information.
• Submit. The EIN is issued immediately on completion, and you can download and print the confirmation to use the same day.

The online application takes roughly ten minutes and is available during the IRS's posted hours. One responsible party — typically a managing partner — completes it on behalf of the firm.

The responsible party

The IRS requires a "responsible party" — a real person who controls or manages the firm — with a valid U.S. taxpayer ID (Social Security number or ITIN) to apply online. This is usually one of the partners. The EIN belongs to the partnership, not to that individual; the responsible party is simply the human the IRS attaches to the application.

The online tool covers most firms, but a couple of situations require an alternate path.

No U.S. taxpayer ID

If the responsible party doesn't have a U.S. Social Security number or ITIN, the online application won't work. In that case, the firm applies using Form SS-4, submitted by fax or mail to the IRS. This is common for partnerships with foreign partners. Fax processing is faster than mail — often a few business days — while mailed applications take longer, so fax when you can.

Getting the form right

Whether online or on paper, accuracy matters. The firm's legal name on the EIN application should match the name registered with the Wisconsin DFI. A mismatch between your federal EIN records and your state registration can cause friction later — at the bank, with the state, or at tax time. Take the extra minute to make sure the name and address are exactly consistent across your federal and state paperwork.

The EIN is issued once and stays with the partnership. Put the confirmation somewhere safe and treat the number as sensitive information.

What to do with it

• Store the confirmation. Save the IRS confirmation (the CP 575 notice or the online printout) with your firm's permanent records alongside your DFI registration and partnership agreement.
• Open the bank account. With the EIN and your accepted Statement of Qualification in hand, open a partnership bank account so firm and personal finances stay cleanly separated.
• Set up tax accounts. Use the EIN to register any Wisconsin Department of Revenue accounts the firm needs — sales tax, withholding — and for federal payroll setup if you'll have employees.
• Use it on filings. The EIN goes on the firm's partnership return and on the K-1s issued to partners.

You generally keep the same EIN

A partnership normally keeps its EIN for its entire life. You typically only need a new one in specific circumstances — for example, certain changes in the entity's structure. Routine changes, like moving offices or switching registered agents, don't require a new EIN. If you're unsure whether a structural change triggers a new number, that's a question for your accountant.