How to Fill Out Form W-9 for LLC: A Complete Guide

Form W-9 lines 1 through 9, for an LLC

Before getting into the classification-specific detail, here’s what an LLC needs to know about the general structure of the form itself:

• Line 1, Name: The name that matches what’s on file with the IRS. For a disregarded single-member LLC, this is the owner’s name, not the LLC’s name.
• Line 2, Business name/disregarded entity name: Where the LLC’s name goes if it’s different from Line 1, most commonly for a
  single-member LLC operating under its own name while being disregarded from its owner for
  tax purposes.
• Line 3, Federal tax classification: The checkbox and classification code section covered in detail below. This is where nearly all
  LLC-specific errors occur.
• Line 3b: Relevant only to certain partnerships, trusts, or estates with foreign owners. Covered in its own section below.
• Line 4, Exemptions: Generally left blank by most LLCs, unless the LLC qualifies for a specific payee or FATCA exemption code.
• Line 5 and 6, Address: The LLC’s or owner’s current mailing address.
• Line 7, Account number(s): Optional, used only if the requester needs to match the form to a specific account.
• Part I, TIN: The correct taxpayer identification number, which depends entirely on the classification made in Line 3, covered in its own section below.
• Part II, Certification: The signature confirming the information provided is accurate, including that backup withholding does not apply unless otherwise indicated.

With that structure in mind, here’s how an LLC completes these lines differently depending on its specific classification.

Completing Form W-9 as a single-member LLC

A single-member LLC that has not elected to be taxed as a corporation is, by default, a disregarded entity. For federal tax purposes, the IRS treats the LLC as if it doesn’t exist separately from its owner.

On Form W-9, a single-member LLC should:

• Enter the owner’s name on Line 1, not the LLC’s name (the LLC’s name can go on Line 2 as a “doing business as” name)
• Check “Individual/sole proprietor or single-member LLC” on Line 3, not the “LLC” box
• Provide the owner’s SSN or EIN, not a separate EIN for the LLC, unless the owner has specifically assigned the LLC its own EIN for
  other purposes

The IRS instructions for Form W-9 are explicit on this point: A single-member LLC that is disregarded from its owner should not check the “LLC” box unless its owner is itself a non-disregarded LLC. Checking “LLC” as a single-member disregarded entity is the single most frequent classification error on this form.

Completing Form W-9 as a multi-member LLC

An LLC with two or more members is, by default, taxed as a partnership, unless it has elected otherwise.

On Form W-9, a multi-member LLC should:

• Enter the LLC’s legal name on Line 1
• Check the “Limited liability company” box on Line 3
• Enter “P” in the classification field next to that box, indicating partnership tax treatment
• Provide the LLC’s own EIN

Completing Form W-9 as an LLC taxed as a corporation

An LLC can elect to be taxed as a corporation by filing Form 8832 (for C corporation treatment) or Form 2553 (for S corporation treatment). Once that election is made, the LLC completes Form W-9 based on its elected status, not its
default classification.

On Form W-9, an LLC taxed as a corporation should:

• Enter the LLC’s legal name on Line 1
• Check the “Limited liability company” box on Line 3
• Enter “C” for C corporation or “S” for S corporation in the classification field
• Provide the LLC’s own EIN

This applies regardless of whether the LLC has one member or several. Corporate election overrides the default single-member or
partnership treatment.

The Line 3 checkbox, explained

Line 3 of Form W-9 is where nearly every LLC-related error happens. Here’s a side-by-side summary:

If you’re unsure which category applies, check whether Form 8832 or Form 2553 was ever filed for the LLC. If neither was filed, the LLC falls into its default classification based on its number of members.

Understanding Line 3b: Flow-through entities with foreign owners

The March 2024 revision of Form W-9 added Line 3b, a checkbox that didn’t exist on earlier versions of the form. This line applies to a partnership, trust, or estate that has one or more foreign partners, owners, or beneficiaries.

If your LLC is taxed as a partnership and has any foreign partners, Line 3b should be checked to indicate that the entity may have obligations under IRC Section 1446 relating to withholding on foreign partners’ shares of income.

Providing your TIN correctly as an LLC

Which taxpayer identification number belongs on Form W-9 depends on the same classification logic used for Line 3:

• A disregarded single-member LLC provides the owner’s SSN, or the owner’s EIN if the owner is a business
• A multi-member LLC taxed as a partnership provides the LLC’s own EIN
• An LLC taxed as a corporation provides the LLC’s own EIN

Providing the wrong TIN, most often an LLC’s own EIN when the owner’s SSN was required, is a frequent cause of “B-Notices” from the IRS, where the name and TIN combination on a filed 1099 doesn’t match IRS records.

Backup withholding and LLCs

If an LLC fails to provide a valid TIN, or the IRS notifies the payer that the TIN provided doesn’t match its records, the payer is required to apply backup withholding at a flat 24% rate on future payments.

This applies to LLCs the same way it applies to any other payee. Completing Form W-9 accurately the first time, particularly the classification and TIN fields, is the most effective way to avoid this.

If you’re requesting a W-9 from an LLC vendor

If your business is the one requesting a completed W-9 from an LLC vendor or contractor, a few things are worth checking before you file:

• Confirm the classification checkbox and TIN match the pattern above for the LLC’s stated structure. A single-member LLC providing its own EIN and checking “LLC” instead of “Individual/sole proprietor” is a common inconsistency worth flagging back to the vendor before you rely on it for 1099 reporting.
• Run a TIN match against the IRS database before filing, to catch a name and TIN mismatch early rather than after you’ve already filed
  a 1099.
• Keep the completed W-9 on file. You don’t submit it to the IRS, but you need it to support how you classified and reported payments to that vendor.

Learn more about TIN matching and W-9 collection in our W-9 Manager guide.

Frequently asked questions