For a single-member LLC taxed under the default rules, either your Social Security number or the LLC’s EIN is acceptable on Form W-9, as long as your personal name appears on Line 1. The IRS treats the LLC as a disregarded entity and looks through it to you, so the matching happens on your name. The choice between SSN and EIN on a single-member LLC W-9 is really a privacy question. It changes only if your LLC has elected to be taxed as an S- or C-corporation, in which case the EIN is the only correct answer.
Choosing Between Your SSN and the LLC’s EIN
The IRS guidance for disregarded entities says to use “the name and TIN of the single member owner for federal tax purposes.”1Internal Revenue Service. Single Member Limited Liability Companies Your SSN is the default and works cleanly. Your 1099 gets filed under your name and SSN, and the IRS matches it to your personal return.
If your LLC has an EIN, you can use that instead. The 1099 still gets filed under your name on Line 1, just with the EIN in place of the SSN. Because the IRS matching system keys off the name, there’s no mismatch. Many owners prefer this route to avoid handing their SSN to every client and vendor. The tax obligation is identical either way: the income still lands on your personal return.
Whichever number you choose, be consistent with a given payer. Two different payers can hold two different numbers for you without a problem, but if you ever switch a payer from your SSN to your EIN, send them an updated W-9 so their records match what they’ve been filing.
When You Need an EIN Regardless
Some situations require you to have an EIN whether or not you plan to put it on the W-9.1Internal Revenue Service. Single Member Limited Liability Companies
- If your LLC has any employees, you need an EIN for payroll tax filings.
- Excise tax returns (Forms 720, 730, 2290, or 11-C) require the LLC’s EIN, not your SSN.
- Some states require an EIN for state-level tax registration or annual reporting.
- Most banks require an EIN to open a business account in the LLC’s name.
If none of those apply and you already run everything under your SSN, you’re not obligated to get an EIN just for the W-9.
Filling Out the W-9 So Your TIN Actually Matches
The number in Part I only works if the rest of the form is right. The W-9 was revised in March 2024, and Line 3a in particular is where disregarded entities get tripped up.
Line 1 and Line 2
Your full legal name, as it appears on your personal tax return, goes on Line 1. Your LLC’s legal name, trade name, or DBA goes on Line 2.2Internal Revenue Service. Form W-9 (Rev. March 2024) Reversing these is the most common mistake. The LLC’s name should never appear on Line 1 for a disregarded entity.
Line 3a
Do not check the “Limited liability company” box. A disregarded entity checks the box that matches the tax classification of the owner. For most single-member LLC owners, that’s “Individual/sole proprietor or single-member LLC.”2Internal Revenue Service. Form W-9 (Rev. March 2024) The instructions state it directly: “A disregarded entity should instead check the appropriate box for the tax classification of its owner.”3Internal Revenue Service. Instructions for the Requester of Form W-9 (03/2024) The LLC box with a C, S, or P code is reserved for LLCs that have elected corporate or partnership status.
Part I
Enter either your SSN or your LLC’s EIN. As long as Line 1 shows your name, either number matches. Don’t put both.
If Your LLC Elected S- or C-Corp Taxation
Everything above assumes the default disregarded status. If you filed Form 2553 for S-corporation treatment or Form 8832 for C-corporation treatment, the LLC is no longer disregarded.4Internal Revenue Service. About Form 2553, Election by a Small Business Corporation5Internal Revenue Service. About Form 8832, Entity Classification Election It’s a separate taxable entity that files its own return, and the W-9 changes to match.
Line 1 gets the LLC’s legal name, not yours. On Line 3a, you check the “Limited liability company” box and enter C or S for the classification.2Internal Revenue Service. Form W-9 (Rev. March 2024) In Part I, the LLC’s EIN is required. Your personal SSN is not an option here, because the payer’s 1099 (if any is issued) needs to match the LLC’s corporate return.
What Goes Wrong When the W-9 Is Filled Out Incorrectly
If a payer doesn’t have your TIN when making a reportable payment, or the IRS tells them your name and TIN don’t match, they’re required to withhold 24% of the payment and remit it to the IRS.6Internal Revenue Service. Backup Withholding Due to Missing Payee TIN (Publication 7951) You’ll receive a “B-notice” first, and if you don’t correct the information, backup withholding kicks in on future payments.7Internal Revenue Service. IRS Sends CP2100 and 2100A Notices When Payers Need To Correct Backup Withholding Errors You can recover it as a credit on your return, but living without 24% of your gross income for months is a real cash-flow problem.
Failing to furnish a correct TIN when required also carries a penalty of $50 per failure, up to $100,000 per calendar year, and it falls on the person who failed to provide the number.8Internal Revenue Service. 20.1.7 Information Return Penalties
The most common mismatch for a single-member LLC is putting the LLC’s name on Line 1 rather than the owner’s name. The payer files a 1099 under the LLC’s name, the IRS can’t match it, and a CP2100 notice goes out. Get Line 1 right, and either your SSN or your EIN works in Part I.