EIN Guide for an Oregon Limited Partnership

An Employer Identification Number, or EIN, is a nine-digit number the IRS assigns to a business. It functions as the business's federal tax identifier — the entity-level equivalent of a Social Security number. For a limited partnership, an EIN is not a nice-to-have; it is effectively mandatory.

Why the LP structure requires one

A limited partnership has more than one owner by definition — at least one general partner and one limited partner. Multi-owner entities file a partnership tax return (Form 1065) with the IRS, and that return is filed under the partnership's EIN. There is no version of an operating LP that gets by on an individual's Social Security number the way a single-member LLC sometimes can. The moment your LP exists and does anything, it needs its own federal number.

What you use it for

• Filing the partnership return — Form 1065 and the Schedule K-1s issued to partners
• Opening a business bank account — banks require the LP's EIN, not a partner's SSN
• Hiring employees and running payroll — payroll tax deposits and filings run on the EIN
• Registering for state tax accounts where the LP's activities require them
• Establishing the LP's identity with vendors, lenders, and licensing bodies

Timing matters. You want the LP to legally exist before you get its EIN, and you want the EIN before you try to open a bank account.

Form the LP first

Apply for the EIN after the Oregon Secretary of State accepts your Certificate of Limited Partnership. The EIN application asks for the entity's legal name and formation details, so having the accepted certificate in hand means the information you enter matches the state record. Applying before the LP exists invites mismatches that cause headaches later.

What the application asks for

• The LP's exact legal name as it appears on the filed certificate
• The formation state (Oregon) and formation date
• The mailing address for the partnership
• The responsible party — a general partner who controls or manages the LP, with their SSN or ITIN
• The reason for applying (started a new business) and details like expected employees

The responsible party

The IRS requires a "responsible party" — a real person who ultimately controls the entity, not another entity. For an LP, this is typically a general partner. If the general partner is itself an entity (an LLC serving as general partner, for instance), the responsible party is the individual who controls that entity. The responsible party's SSN or ITIN is what lets you complete the online application.

The IRS issues EINs at no cost. The fastest and simplest way is the online application, and it is the route to use whenever the responsible party has a US Social Security number or ITIN.

Online application

Go to the EIN Assistant on IRS.gov. The application is a short interview — entity type, formation details, responsible party, reason for applying. It takes about ten minutes, and the EIN is issued immediately at the end. You can download the confirmation letter (the CP 575) and start using the number the same day. Complete the session in one sitting; the tool times out if you leave it idle.

Choose the right entity type

When the application asks for entity type, select the partnership classification — a limited partnership files as a partnership by default. Do not select LLC or corporation; those are different structures with different return requirements. Choosing the wrong type here creates a mismatch that is annoying to unwind later.

Beware paid "EIN services"

Because the EIN is free and the application is short, there is no reason to pay a third party a fee just to obtain the number. Any site charging a standalone fee to "get your EIN" is charging for a free federal form. When Mainstay Filing forms your LP, we can guide you through the application so it is done correctly without you paying for the number itself.

The online route works cleanly when the responsible party has an SSN or ITIN. When they do not, the process changes, and this is where non-US and out-of-state partners most often get stuck.

No SSN or ITIN

If the responsible party is a non-US person without a Social Security number or ITIN, the online application will not work. Instead, you complete IRS Form SS-4 and submit it by fax or mail. The IRS processes these manually — fax turnaround is typically a couple of weeks, and mail is longer. Plan for the delay if a foreign partner is the responsible party, because it can hold up opening the LP's bank account.

International applicants by phone

The IRS maintains a dedicated line for international applicants who need an EIN and cannot use the online tool. A responsible party located outside the US can sometimes obtain the EIN over the phone, which is faster than fax or mail. Have a completed Form SS-4 in front of you when you call so you can answer every question accurately.

Keep the responsible party accurate

Whoever you list as the responsible party is on record with the IRS as controlling the entity. If that person later leaves the partnership, the IRS expects you to update the responsible party using Form 8822-B. Keeping this current avoids confusion if the IRS ever needs to reach the LP.

The EIN is a permanent identifier for the LP. Once you have it, a few practical steps put it to work and keep it clean.

Store the confirmation

Save the CP 575 confirmation letter with your formation documents. Banks and lenders sometimes ask to see it, and it is the cleanest proof of the LP's EIN. If you lose it, the IRS can provide a replacement confirmation (a 147C letter) on request, but keeping the original is easier.

Open the bank account

With the accepted Certificate of Limited Partnership and the EIN confirmation in hand, you can open the LP's business bank account. Keeping the partnership's money in its own account, separate from any partner's personal funds, is fundamental to running the LP cleanly.

Use it consistently

Use the EIN on the partnership's tax filings, payroll, and business paperwork. The number never expires and does not need renewal. If the LP is ever dissolved, you do not "cancel" the EIN — it simply stays associated with that closed entity, and you notify the IRS that the business account is being closed as part of your final filings.