Backup Withholding on W-9: Triggers, Stopping It, and Penalties

Backup withholding on a W-9 is a 24% federal tax that a payer must deduct from payments to you — interest, dividends, freelance income, and most other 1099-reportable income — when the IRS has reason to think the money won’t be reported. Returning a complete, signed Form W-9 with your correct Taxpayer Identification Number, and a valid certification that you aren’t already flagged, is what keeps that 24% off your payments.

What Backup Withholding Actually Is

Under 26 U.S.C. § 3406, backup withholding runs at a flat 24% of the gross payment.¹ The payer subtracts that percentage before paying you and sends it to the IRS in your name. It is not an added tax. It is a prepayment against whatever you end up owing for the year, functioning much the way paycheck withholding does for a regular employee.

The rule reaches most income reported on a Form 1099: interest (1099-INT), dividends (1099-DIV), independent contractor pay (1099-NEC), rents and royalties (1099-MISC), broker proceeds (1099-B), certain government payments (1099-G), and gambling winnings on Form W-2G that aren’t already subject to regular gambling withholding. The statute defines “reportable payment” by cross-referencing every code section that requires an information return, so if a 1099 is required, backup withholding can apply.¹

Third-party payment platforms (the apps that settle card and online transactions) work on a higher threshold. Backup withholding kicks in only when gross payments to one payee exceed $20,000 and the transaction count exceeds 200 in a calendar year.² Below both, the platform isn’t required to withhold.

What Triggers Backup Withholding

The statute names four situations where the payer has no discretion and must start withholding at 24%.¹

You didn’t furnish a TIN. No W-9 on file, a blank TIN field, or a number with obvious formatting problems all fall here. This is the most common trigger.
The IRS told the payer your name and TIN don’t match its records. That notice is called a “B” notice, and the payer must both begin withholding and ask you for a corrected number.³
The IRS determined you underreported interest or dividends on a prior return and issued a “C” notice directing your payers to withhold on future interest and dividend payments.⁴
You were asked to certify on the W-9 that you’re not subject to backup withholding, and you didn’t.

Payers who ignore any of these become personally liable for the tax they should have collected, so most treat W-9 requests seriously.

Filling Out Form W-9 to Prevent Withholding

A complete, accurate W-9 is the simplest way to keep the 24% off your money. The form is one page of fields, but small mistakes are exactly what start the problem.⁵

Name: your full legal name as it appears on your tax return. Sole proprietors and single-member LLCs put the personal name on line 1 and the business name on line 2.
Federal tax classification: check the one box matching your entity — individual/sole proprietor, C corporation, S corporation, partnership, trust or estate, or LLC with the correct classification letter.
Exempt payee code: individual freelancers and sole proprietors leave this blank. It’s for entities such as tax-exempt organizations, government bodies, and most corporations.⁶
FATCA reporting code: applies only to accounts maintained outside the United States by certain foreign financial institutions. For a U.S. account, leave it blank.⁷
Address: current mailing address so your 1099 arrives at tax time.
TIN: your Social Security Number if you’re an individual, or your Employer Identification Number if you’re a business entity. A wrong or missing number here is the leading cause of backup withholding.

The Certification in Part II

Signing Part II certifies under penalty of perjury that your TIN is correct and that you are not currently subject to backup withholding for underreporting. If the IRS has already notified you that you are subject to backup withholding — through a C notice, for instance — you must cross out item 2 of the certification before you sign. Do not sign as though the notice weren’t there.

Where to Send It

You return the W-9 to the payer who asked for it, never to the IRS. Most payers now accept it through a secure portal, encrypted email, or fax. The IRS permits electronic W-9s as long as the system requires an electronic signature that authenticates the submission and carries the same perjury language as the paper form.⁸ The payer keeps it on file.

One caution before turning in a W-9: if you are not a U.S. person for tax purposes, you use the W-8 series (typically W-8BEN for individuals or W-8BEN-E for entities), not a W-9.⁹ Sending the wrong form creates problems at filing time.

How to Stop Backup Withholding Once It’s Started

The fix depends on what triggered it.

No TIN on File

Submit a properly completed and signed W-9 with your correct TIN. Withholding stops on future payments once the payer has it.

First or Second B Notice

A First B Notice is resolved by giving the payer a new, correctly completed W-9. A Second B Notice raises the bar: a W-9 alone is not enough. You must provide a copy of your Social Security card (for SSN issues) or an IRS Letter 147C verifying your name and EIN (for business TIN issues).³ By the second notice, the IRS has already seen the mismatch once and wants documentary proof rather than a self-reported number.

C Notice

If the trigger was underreported interest or dividends, the fix is to correct the underlying return. File any missing returns with the correct income, or amend prior returns that left out reportable interest or dividends.⁴ You don’t need to call or write the IRS separately to confirm the correction; filing the return is the correction. The IRS then notifies your payer when withholding should stop. For questions specific to a C notice, the IRS runs a dedicated line at 800-829-0922 or 800-829-8374, weekdays 8:30 a.m. to 4:30 p.m. ET.

One thing a valid W-9 will not do: it doesn’t refund what’s already been withheld. Any amount taken out before the payer received a valid form stays with the IRS until you claim it on your return.

Getting Credit for Amounts Already Withheld

Backup withholding counts as a credit toward your tax liability for the year, the same way paycheck withholding does. The withheld amount appears in Box 4 of the Form 1099 (or Form W-2G) the payer sends you, and it flows to the “Federal income tax withheld” line on your Form 1040.¹⁰ The statute treats it as if it were regular wage withholding for credit purposes.¹ If 24% is more than you actually owe on that income, the excess comes back as a refund. That’s common when your effective rate is well under 24%.

Penalties for a False W-9

The certification you sign on the W-9 carries teeth. Falsely certifying that you’re not subject to backup withholding, or providing an incorrect TIN to reduce withholding, is a $500 civil penalty per false statement.¹¹ The IRS can waive that penalty if your total tax liability for the year doesn’t exceed your credits. Willfully making a false certification tied to backup withholding is also a criminal offense, punishable by a fine of up to $1,000, imprisonment for up to one year, or both.¹² If a notice tells you that you’re subject to backup withholding, sign the W-9 accordingly rather than certifying otherwise.

1
Office of the Law Revision Counsel. 26 USC 3406 – Backup Withholding
2
Internal Revenue Service. Treasury, IRS Issue Proposed Regulations Reflecting Changes From the One, Big, Beautiful Bill to the Threshold for Backup Withholding on Certain Payments Made Through Third Parties
3
Internal Revenue Service. Backup Withholding “B” Program
4
Internal Revenue Service. Backup Withholding “C” Program
5
Internal Revenue Service. About Form W-9, Request for Taxpayer Identification Number and Certification
6
eCFR. 26 CFR 31.3406(g)-1 – Exception for Payments to Certain Payees and Certain Other Payments
7
Internal Revenue Service. Form W-9 (Rev. March 2024)
8
Internal Revenue Service. Instructions for the Requester of Form W-9
9
Internal Revenue Service. About Form W-8 BEN, Certificate of Foreign Status of Beneficial Owner for United States Tax Withholding and Reporting (Individuals)
10
Internal Revenue Service. Backup Withholding
11
Office of the Law Revision Counsel. 26 USC 6682 – False Information With Respect to Withholding
12
Office of the Law Revision Counsel. 26 USC 7205 – Fraudulent Withholding Exemption Certificate or Failure to Supply Information