W-9 for LLCs
The single line that confuses every LLC owner — finally explained clearly.
By Reba Donaldson · Last reviewed: April 2026
The confusion source
Line 3 of the W-9 has separate checkboxes for different tax classifications. The LLC checkbox has a small text field next to it asking you to enter "C", "S", or "P" — and the form gives almost zero guidance on which to use.
The trick: your LLC's tax classification is not the same as your LLC's legal structure. The IRS classifies LLCs based on how they're taxed, not how they're organized. Same LLC can be classified four different ways depending on tax elections.
The four scenarios
Scenario 1: Single-member LLC, no special tax election
Don't check the LLC box. Check the "Individual / sole proprietor / single-member LLC" box instead.
Single-member LLCs default to "disregarded entity" status — the IRS taxes you as a sole proprietor and ignores the LLC for tax purposes. Use your SSN (or EIN if you got one for privacy/banking).
This is most common scenario for solo freelancers and consultants who formed an LLC for liability protection.
Scenario 2: Multi-member LLC, no special tax election
Check the LLC box and write "P" for partnership.
Multi-member LLCs default to partnership taxation. The LLC files Form 1065 and issues K-1s to each member. Use the LLC's EIN.
Scenario 3: LLC taxed as S-corporation
Check the LLC box and write "S".
If you've filed Form 2553 to elect S-corp tax treatment, your LLC files Form 1120-S and issues K-1s. Common for higher-earning service businesses to save on self-employment tax. Use the LLC's EIN.
Scenario 4: LLC taxed as C-corporation
Check the LLC box and write "C".
Rare. If you've filed Form 8832 to elect C-corp treatment, your LLC files Form 1120 and pays corporate tax. Use the LLC's EIN.
Quick reference
| Your LLC | Box to check | TIN to use |
|---|---|---|
| Single-member, default | Individual/SP/SMLLC | SSN or EIN |
| Single-member, S-corp election | LLC, write "S" | EIN |
| Single-member, C-corp election | LLC, write "C" | EIN |
| Multi-member, default | LLC, write "P" | EIN |
| Multi-member, S-corp election | LLC, write "S" | EIN |
| Multi-member, C-corp election | LLC, write "C" | EIN |
The Line 1 trap for single-member LLCs
If you're a single-member LLC, what name goes on Line 1 of the W-9 — your name or your LLC's name?
Your personal legal name goes on Line 1. Your LLC's name goes on Line 2 (Business name). This is because the IRS considers single-member LLCs disregarded entities — your LLC is not a separate taxpayer in their eyes.
Example: You operate "Acme Consulting LLC" as a single-member LLC under your own personal taxes.
- Line 1: Your full legal name (e.g., "Jane Smith")
- Line 2: Acme Consulting LLC
- Line 3: Check "Individual / sole proprietor / single-member LLC"
- TIN: Your SSN (or your EIN if you got one)
If you elected S-corp tax treatment for your LLC, then the LLC name goes on Line 1 and you check the LLC box with "S" — because the IRS now sees the LLC as a separate taxpayer.
Why this matters
Mismatched W-9 information is a leading cause of backup withholding. If you check the LLC box and use your SSN (instead of your EIN), the IRS computer match will fail because the SSN is filed under your personal name, not the LLC name. Suddenly 24% of your payments are going to the IRS.
The fix: make sure the name on Line 1 matches the TIN you provide. If the TIN is your SSN, Line 1 should be your personal name. If the TIN is the LLC's EIN, Line 1 should be the LLC name (and you should be a multi-member LLC or have a corporate tax election).