To verify a W-9, run the payee’s legal name and Taxpayer Identification Number through the IRS TIN Matching service, confirm the business is active in the state where it claims to be registered, and resolve any mismatch before you file a 1099. That combination catches the errors that otherwise trigger IRS notices, backup withholding at 24%, and per-return penalties. Verification is free, and the diligence itself is what protects you if something later turns out to be wrong.
What the Form Should Tell You
A W-9 collects a small set of data points, and each one has a job on your year-end 1099. The pairing that matters most is Line 1 (the payee’s legal name) and the nine-digit TIN. For individuals, the TIN is usually a Social Security Number; for businesses, an Employer Identification Number.1IRS. Form W-9 (Rev. March 2024) Request for Taxpayer Identification Number and Certification Sole proprietors and certain resident aliens may use an Individual Taxpayer Identification Number.2Internal Revenue Service. U.S. Taxpayer Identification Number Requirement The Line 1 name has to match exactly what the IRS has on file. A middle initial that isn’t in the IRS record, a missing suffix, a married name that was never updated with the Social Security Administration — any of those will produce a mismatch.
Check the federal tax classification too. It tells you whether the payee is a corporation, partnership, LLC, or individual, and it decides whether you need to file a 1099 at all. Payments to C and S corporations are generally exempt from 1099-NEC reporting. The exempt payee code is the other field to read carefully: it identifies entities not subject to backup withholding, including tax-exempt organizations under Section 501(a), government agencies, corporations, and registered securities dealers.1IRS. Form W-9 (Rev. March 2024) Request for Taxpayer Identification Number and Certification If a payee claims an exemption they aren’t entitled to, you can end up failing to withhold when the law required you to.
The Sole Proprietor and Single-Member LLC Pitfall
Most name/TIN mismatches trace back to the same mistake. Sole proprietors and single-member LLCs treated as disregarded entities have to put the owner’s individual name on Line 1, not the business name. The business or DBA name belongs on Line 2.1IRS. Form W-9 (Rev. March 2024) Request for Taxpayer Identification Number and Certification The IRS matches the TIN against the Line 1 name, so a vendor who writes “Smith Consulting LLC” on Line 1 and provides a personal SSN will fail TIN matching every time.
The TIN itself follows the same rule. A single-member LLC classified as a disregarded entity should give you the owner’s SSN or EIN, not the LLC’s separate EIN. The LLC’s EIN is only used for employment tax and excise tax filings.3Internal Revenue Service. Single Member Limited Liability Companies When a W-9 arrives from a single-member LLC listing the entity’s EIN, ask the vendor to confirm which number the IRS ties the entity to before you run the match. That single question resolves a large share of the mismatches you’d otherwise have to chase down after the fact.
Running the IRS TIN Match
The IRS TIN Matching service is free. You access it through the IRS e-Services portal, which requires a registered account and a designated responsible official. The IRS validates the registration information before granting access, so expect several days between applying and being able to log in.4Internal Revenue Service. Taxpayer Identification Number (TIN) Matching Tools
Two modes are available. Interactive matching accepts up to 25 name/TIN pairs per session and returns results in seconds. Bulk matching accepts up to 100,000 pairs in a single text file, with results returned within 24 hours. Small operations that onboard a few contractors a month can work interactively. Higher-volume payers use the bulk upload.
Enter each name and TIN exactly as they appear on the W-9. The system returns a one-digit result code for each entry. Code 0 is what you want: the name and TIN match IRS records. The other codes signal problems:5Internal Revenue Service. IRS Publication 2108
- Code 1 — TIN missing or not in the correct format.
- Code 6 — TIN has not yet been issued by the IRS or SSA.
- Code 7 — Name and TIN combination does not match IRS records.
- Code 8 — Mismatch requiring follow-up, similar to Code 7.
A non-zero code doesn’t mean the vendor lied. Recent name changes, freshly issued EINs still working through the system, and simple typing errors are the common causes. What it does mean is that you can’t file a correct 1099 with the information in front of you.
Confirming the Entity Actually Exists
TIN matching confirms the tax identity. It says nothing about whether the business is a real legal entity in good standing. For that, search the Secretary of State database (or the equivalent registry) in the state where the entity claims to be organized. Most states offer free online searches. Look for a status of “Active” or “Good Standing,” which means the entity is authorized to do business and enter contracts.
A status of “Inactive,” “Dissolved,” or “Administratively Revoked” usually means the entity failed to file annual reports or pay required fees. It isn’t proof of fraud, but it’s a reason to ask questions before you contract or pay. If you need a formal certificate of status for your compliance file, most states charge a modest fee, typically ranging from $5 to $50 depending on the state and whether you need expedited processing.
When the TIN Doesn’t Match
Two things can put you in mismatch territory: your own TIN Match returns a non-zero code, or the IRS sends you a CP2100 or CP2100A notice. Either way, request a corrected W-9 from the payee. If the TIN is missing or clearly wrong, start backup withholding immediately.6Internal Revenue Service. Backup Withholding “B” Program
For name/TIN mismatches flagged by a CP2100, the IRS uses a two-tier B-Notice process. The first time a payee appears on your notice, send them a First B-Notice with a blank Form W-9 within 15 business days of the CP2100 date. A properly completed W-9 resolves the issue. If the same payee shows up again within a three-year period, send a Second B-Notice — and this time a new W-9 isn’t enough. The payee has to provide a copy of their Social Security card or an IRS Letter 147C confirming the name and EIN. A payee who ignores either notice stays subject to backup withholding on every future payment until they respond.6Internal Revenue Service. Backup Withholding “B” Program
Backup Withholding at 24%
Once backup withholding is triggered, you deduct 24% from every reportable payment to the payee and send it to the IRS.7Internal Revenue Service. Backup Withholding The triggers include the payee failing to give you a TIN, the IRS telling you the TIN is incorrect, and the payee failing to certify they aren’t subject to withholding for underreported income.8Office of the Law Revision Counsel. 26 USC 3406 – Backup Withholding
The financial risk sits with you as the payer. If you should have withheld and didn’t, the IRS can hold you liable for the uncollected tax plus interest. Backup withholding is not optional once a triggering event occurs.
One recent change: for 2026, the aggregate reportable payment threshold for payments subject to backup withholding under Sections 6041(a) and 6041A(a) rose from $600 to $2,000, with inflation adjustments in later years.9Internal Revenue Service. Publication 15 (2026)
Penalties for Filing With Bad Information
A 1099 filed with a wrong TIN carries per-return penalties under IRC 6721, adjusted each year for inflation. For returns due in 2026:10Internal Revenue Service. Information Return Penalties
- Corrected within 30 days of the due date: $60 per return.
- Corrected after 30 days but by August 1: $130 per return.
- Filed after August 1 or not corrected at all: $340 per return.
- Intentional disregard: $680 per return, with no annual cap.
For businesses with gross receipts over $5 million, the annual maximum across all returns reaches $3,000,000.11Office of the Law Revision Counsel. 26 USC 6721 – Failure to File Correct Information Returns IRC 6722 imposes separate penalties for furnishing incorrect statements to the payees themselves, so a single bad TIN can generate liability from two directions.
Running TIN matching before you file is the most direct defense. If the error came from information the payee gave you and you can show you verified it through the IRS system, you have a strong reasonable-cause argument. The IRS evaluates reasonable cause case by case and looks for ordinary business care, which is exactly what documented TIN matching demonstrates.
Keeping the Records
Keep every W-9 for at least four years after the tax year the related payments were reported. General IRS guidance for supporting records is three years from the filing date, but employment-related records carry a four-year retention requirement, and applying the longer window to all W-9s is the safer practice.12Internal Revenue Service. How Long Should I Keep Records If you ever need to prove you collected the form, ran the match, or issued a B-Notice, the paper trail is what does it.
W-9s contain SSNs and EINs, so treat them like any other sensitive financial record. Keep paper copies in locked files with restricted access. Encrypt digital copies and limit access to the people who handle tax reporting or accounts payable. A breach of vendor TINs creates liability for your organization and exposes your vendors to identity theft.