Getting an EIN for a South Dakota Limited Partnership

The IRS assigns each business a nine-digit federal tax ID known as an Employer Identification Number. It identifies your business to the federal government the way a Social Security number identifies an individual. For a limited partnership, an EIN is not optional — it is a practical necessity from day one.

Why an LP always needs one

• The partnership files its own return. Every partnership files Form 1065 and issues Schedule K-1s. That return is filed under the partnership's EIN, not any partner's SSN. There is no version of an LP that skips the partnership return, so there is no version that skips the EIN.
• Banks require it. No bank will open a limited partnership's account without the EIN. Since keeping partnership funds separate from partners' personal money is essential to the entity's integrity, the account — and therefore the EIN — is a must.
• Employees and withholding. If the LP hires anyone, the EIN is the number used for payroll tax reporting and deposits.
• It keeps SSNs off business paperwork. Vendors, banks, and counterparties ask for a tax ID. Giving them the EIN keeps the partners' Social Security numbers out of circulation.

A single-member LLC can sometimes lean on the owner's SSN for federal purposes. A limited partnership cannot — by definition it has multiple partners and files a partnership return, so the EIN is baked into how it works.

Timing matters. The EIN should come after your limited partnership legally exists but before you try to open a bank account or file anything.

The right sequence

1. Form the LP first. File the Certificate of Limited Partnership with the South Dakota Secretary of State and get it accepted. The partnership needs to legally exist before you apply, because the EIN application asks for the entity's formation details.
2. Apply for the EIN. With the LP formed, apply to the IRS. It is fast and free.
3. Open the bank account and set up operations. With the certificate and the EIN in hand, the bank has what it needs.

Applying for the EIN before the LP is formed puts you in the awkward position of registering a business that does not yet exist. Because South Dakota processes online formations the same day, the gap between "LP formed" and "ready to apply for the EIN" is often just hours.

The IRS issues EINs directly and at no cost. Be wary of any site that charges a fee to "get" an EIN — the application itself is always free from the IRS.

The online application

• Go to the IRS EIN Assistant at IRS.gov and start a new application.
• Select partnership as the entity type. A limited partnership applies as a partnership for EIN purposes.
• Provide the LP's legal name exactly as it appears on the certificate, its address, and its formation details.
• Name the responsible party — generally a general partner who controls or manages the partnership — along with that person's SSN or ITIN.
• Submit. The EIN is issued immediately, and you can download and print the confirmation letter to use the same day.

The whole process takes about ten minutes. The online tool is available during IRS business hours, and you must complete it in one session — it does not save partway through.

If you cannot apply online

The online application requires the responsible party to have a US Social Security number or ITIN. If your responsible party has neither — common with foreign general partners — the LP applies by fax or mail using Form SS-4. Fax turnaround is several business days; mail is several weeks. Plan ahead if this is your situation, because it is meaningfully slower than the instant online route.

A few recurring snags are worth knowing before you start.

The "responsible party" must be a real individual

The IRS wants a natural person as the responsible party — a general partner who controls the LP — not an entity, even if the general partner of your LP is itself an LLC or corporation. Identify the actual human behind the controlling interest.

One EIN per entity

Your LP gets one EIN and keeps it. You do not need a new one when partners change or the business evolves. You would only get a new EIN in specific situations, such as certain changes in structure — check IRS guidance rather than assuming.

Match the name to the certificate

The name on the EIN application should match the name on your Certificate of Limited Partnership. Mismatches between your IRS records, your state filing, and your bank paperwork cause friction later, so get it consistent from the start.

Watch for fee-charging middlemen

Search results are full of services that charge to obtain an EIN. The IRS never charges for it. If you would rather not deal with the application at all, that is fine — but understand you are paying for convenience, not for the number itself, which is always free direct from the IRS. If you form your LP through Mainstay Filing, we can point you to the correct free IRS application so you are not overpaying a middleman for a ten-minute form.