Do W-9 Forms Expire? Validity, B-Notices, and Fixes

W-9 forms do not expire. The IRS sets no shelf life on the form, so a payer can rely on the same signed W-9 for years as long as the information on it stays accurate.¹ The form becomes invalid the moment a key detail on it changes, and once that happens the payer needs a fresh one before making the next payment. Getting that wrong exposes the payer to 24% backup withholding on every dollar paid.

What Invalidates a W-9 You Already Have

The IRS instructions put the rule plainly: a W-9 becomes invalid on the date the payer knows, or has reason to know, that the information on it is no longer correct.² At that point the payer has to solicit a new form before relying on the old data for any information return. There is no calendar involved. What matters is whether the name, number, and classification on the paper still match the payee’s current tax records.

The changes that trigger a new W-9 are:

A legal name change from marriage, divorce, or a court order, or a sole proprietor incorporating under a different legal entity name.
A new taxpayer identification number, such as switching from a Social Security Number to an Employer Identification Number, or receiving a new EIN after restructuring.³
A change in federal tax classification, such as converting from a C corporation to an S corporation, or moving from a sole proprietorship to a partnership.³
An address change the payee flags to the payer or marks “NEW” on an updated form.¹
An IRS notice telling the payer that the name and TIN on file do not match the agency’s records.

One boundary sits next to this rule. A payee who originally filed a Form W-8BEN as a nonresident alien and later becomes a U.S. resident under the green card test or substantial presence test has to notify the payer within 30 days and provide a W-9 to replace the W-8BEN.⁴ That is a change of status, not an expiration, but the practical result is the same: the old form no longer works.

When to Ask for a Fresh One Anyway

The IRS does not require payers to collect fresh W-9s on any set schedule. No rule says every year, every three years, or on any other cycle.¹ The only hard requirement is a new one when the payer knows the information has changed.

That said, relying on a five-year-old W-9 from a vendor you pay regularly is risky. Vendors move, incorporate, change names, and rarely think to tell their clients. Most well-run accounts payable departments re-solicit W-9s from active vendors every one to three years even when no change has been flagged. The natural time to do it is late in the calendar year, right before 1099 preparation begins, so any stale data surfaces before returns go out.

For a one-time payment, the calculus is simpler. Collect the W-9 before issuing the first check. It will remain valid as long as no information ever reaches you suggesting it is wrong.

What Happens If You Rely on a Bad W-9

When a payer does not have a valid W-9 on file, the law requires them to withhold 24% of every reportable payment and send it to the IRS.¹ This is not optional. A payer who fails to withhold when required becomes personally liable for the tax. Backup withholding kicks in when:

The payee never submitted a W-9, or submitted one without a TIN.
The TIN is facially invalid, such as the wrong number of digits.
The IRS sends a CP2100 or CP2100A notice telling the payer the name and TIN combination does not match its records.
The IRS has notified the payer that the payee has been underreporting interest or dividend income.
The payee refused to certify that they are not subject to backup withholding.⁵

Withheld amounts are reported and deposited on Form 945, due January 31 of the year after the payments were made. Payers who reported more than $50,000 in withholding on the prior year’s Form 945 deposit on a semiweekly schedule; those at or below $50,000 deposit monthly.⁶

The B-Notice Chain

When the IRS finds a name/TIN mismatch on an information return, it sends the payer a CP2100 or CP2100A notice listing the problem accounts. The payer then works through a two-stage cure process.⁷

The first time a payee appears on one of these notices, the payer sends them a First B-Notice with a blank W-9. The payee cures the problem by returning a properly completed and signed W-9 with the correct information. If the payee does not respond, the payer must begin backup withholding at 24% immediately.⁷

If the same payee shows up on another CP2100 or CP2100A within three years, the payer sends a Second B-Notice, and a new W-9 alone will not cure it. The payee has to provide a copy of their Social Security card or, for an EIN, an IRS Letter 147C confirming the name and number match.⁷ Backup withholding continues until that documentation arrives.

This is where treating an old W-9 as evergreen causes real damage. A vendor who quietly changed their name two years ago generates a mismatch on the 1099, which triggers the CP2100, which triggers the B-Notice, which triggers withholding. Catching the change proactively through a periodic re-solicitation avoids the entire chain.

Verifying Before You File

Payers who want to catch mismatches before they turn into a B-Notice can use the IRS TIN Matching program. It is a free online service that lets payers, or their authorized agents, check whether a name and TIN combination matches IRS records before submitting information returns.⁸ Individual entries can be checked interactively, or a bulk file uploaded. It will not catch every issue, but it flags obvious mismatches in time to request a corrected W-9 before filing.

Fixing an Invalid W-9

If a change has invalidated a W-9 on file, the fix is short: the payee completes a new W-9 with the current name, TIN, and classification, signs it under penalty of perjury, and returns it to the payer. Once the payer has a valid form, backup withholding on future payments stops.¹

For a contractor or vendor who has already had 24% withheld, that money is not lost. The payer reports the withheld amount on the 1099 issued at year end. The payee then claims the full amount as federal tax withheld on Line 25b of Form 1040, and it reduces the tax bill dollar for dollar. If the withholding exceeds the tax owed, the difference comes back as a refund.

1
Internal Revenue Service. Instructions for the Requester of Form W-9 (03/2024)
2
Internal Revenue Service. Instructions for the Requester of Form W-9 (03/2024) – Section: Purpose
3
Internal Revenue Service. Form W-9 (Rev. March 2024)
4
Internal Revenue Service. Instructions for Form W-8BEN
5
Office of the Law Revision Counsel. 26 USC 3406 – Backup Withholding
6
Internal Revenue Service. Instructions for Form 945 (2025)
7
Internal Revenue Service. Backup Withholding B Program
8
Internal Revenue Service. Taxpayer Identification Number (TIN) Matching