Getting an EIN for Your Delaware Limited Partnership

An Employer Identification Number is a nine-digit federal tax ID the IRS issues to businesses. Think of it as a Social Security number for the entity — it identifies the partnership on tax filings, bank applications, and payroll.

Why a limited partnership needs one

For an LP, an EIN isn't really optional. A limited partnership has more than one owner, so for federal tax purposes it's treated as a partnership and must file an informational return, Form 1065, issuing Schedule K-1s to the partners. You can't file that return or issue those K-1s without an EIN. In practice, the EIN is one of the first things you get after the LP is formed.

Where you'll use it

• Filing the partnership's federal return (Form 1065) and issuing K-1s
• Opening a business bank account — banks require the EIN for a partnership account
• Hiring employees and running payroll
• Applying for certain licenses and permits
• Establishing the LP's credit and dealing with vendors that require it

Keeping the EIN on the entity also means partners' personal Social Security numbers stay off routine business paperwork.

Sequence matters. The right time to get the EIN is after Delaware has accepted your Certificate of Limited Partnership, not before.

Why order matters

The EIN application asks for the legal name of the entity and its formation details. If you apply before the LP officially exists, you risk a mismatch between the IRS record and the state record — the kind of small inconsistency that causes headaches when you open a bank account or file taxes. Form the LP first, confirm the name as accepted by Delaware, then apply for the EIN using that exact name.

One EIN per entity

A partnership gets one EIN. If you restructure — say you later convert to a different entity type or the partnership terminates and a new one forms — the IRS may require a new EIN. For a straightforward, continuing LP, though, the single EIN you obtain at the start carries the entity through its life.

The IRS issues EINs directly, at no cost. Be wary of third-party sites that charge a fee to "get" an EIN — the IRS doesn't charge for it.

Applying online (the fastest way)

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

• Takes roughly ten minutes to complete
• Issues the EIN immediately upon completion — you can download the confirmation and start using the number the same day
• Is available during the IRS's posted hours for the tool

To complete the online application, the responsible party — generally a general partner or the person who controls the entity — needs a valid US Social Security number or ITIN.

Applying by fax or mail

If you can't or prefer not to apply online, file Form SS-4 by fax or mail. Fax turnaround is typically a few business days; mail takes longer. This is the standard route when the responsible party lacks an SSN or ITIN, which is common for non-US partners.

The EIN application is short, but a couple of fields trip people up — especially for partnerships with international partners.

What you'll provide

• The legal name of the LP exactly as accepted by Delaware
• The entity type — you'll indicate it's a partnership
• The responsible party's name and taxpayer ID (SSN or ITIN)
• The reason for applying (started a new business) and the number of expected employees
• A US mailing address for the entity and, if relevant, the state where it operates

The responsible party

The IRS wants a single individual who ultimately controls the entity as the responsible party — typically a general partner. It should be a real person, not another entity, in most cases.

The non-US partner wrinkle

The online EIN Assistant requires the responsible party to have an SSN or ITIN. If your responsible party is a non-US person without one, you can't use the online tool — you apply instead by submitting Form SS-4 by fax or mail, where an SSN/ITIN isn't required for the responsible party in the same way. This is a routine path for foreign-owned Delaware LPs; it just takes longer than the instant online option.

Getting an EIN is genuinely simple once your LP exists, and the IRS charges nothing for it. Because the application is free and quick, the most valuable thing is getting the sequence right: form the LP, confirm the accepted name, then apply.

Mainstay Filing focuses on the Delaware side — preparing and filing your Certificate of Limited Partnership and serving as your registered agent — which is the step that has to come first. With the accepted formation document in hand, you have exactly what the EIN application needs: the LP's confirmed legal name and formation details.

We're a filing and agent service, not a tax advisor. We don't determine your partnership's tax elections or complete your Form 1065. Deciding who should be the responsible party, and how the LP should be taxed, are questions for your CPA. What we make sure of is that the Delaware formation — the prerequisite for a clean EIN — is done correctly.