Businesses normally pay independent contractors, vendors and other nonemployee service providers without withholding federal income tax from each payment.
That is one of the major differences between paying an employee through payroll and paying an independent contractor or vendor.
However, there are situations where the IRS requires a payer to begin backup withholding.
The current federal backup withholding rate is 24%. When backup withholding applies, the business generally deducts 24% from certain reportable payments and sends that amount to the IRS instead of paying the entire amount to the recipient.
Backup withholding can arise when a contractor or vendor fails to provide a taxpayer identification number, provides incorrect information, receives an IRS TIN mismatch notice, or becomes subject to withholding because of certain IRS notifications.
For businesses that regularly issue Forms 1099, understanding backup withholding is an important part of vendor onboarding and tax-information reporting.
A missing or incorrect W-9 should not simply be treated as a paperwork inconvenience.
It can eventually create a withholding and reporting obligation.
What Is Backup Withholding?
Backup withholding is federal income tax withholding that applies to certain reportable payments when specified tax-information problems exist.
In most contractor relationships, businesses do not withhold federal income tax from the contractor’s payment.
For example, if a graphic designer invoices a company for $2,000, the company might normally pay the full $2,000 and later report the qualifying payment on the appropriate Form 1099.
Backup withholding changes that process.
If the designer becomes subject to backup withholding, the payer may instead be required to withhold:
24% of the reportable payment
and remit the withheld amount to the IRS.
The contractor receives the remainder.
The IRS explains that backup withholding exists to help ensure that federal tax is collected on reportable income when certain taxpayer-identification or reporting problems occur.
What Is the Backup Withholding Rate in 2026?
The federal backup withholding rate is currently:
24%
The IRS instructions for Form W-9 requesters state that payers subject to the backup-withholding rules must generally deduct, withhold and deposit 24% of reportable payments until the reason for backup withholding has been resolved.
This is different from ordinary payroll withholding.
It is also different from withholding rules that may apply to foreign persons.
Backup withholding discussed in this article generally concerns reportable payments to U.S. persons under the applicable information-reporting rules.
When Can Backup Withholding Be Required?
The IRS identifies several circumstances that can trigger backup withholding.
These include situations where:
- The payee fails to provide a taxpayer identification number in the required manner.
- The IRS tells the payer that the taxpayer identification number provided is incorrect.
- The IRS determines that the payee underreported certain interest or dividend income.
- The payee fails to make a required certification concerning backup withholding.
For contractors and vendors, the most common practical issues are usually:
Missing TIN
or
Incorrect name/TIN combination.
What Is a TIN?
TIN means:
Taxpayer Identification Number.
Depending on the taxpayer, this can include:
- Social Security Number
- Employer Identification Number
- Individual Taxpayer Identification Number
Businesses commonly collect this information from U.S. contractors and vendors using:
Form W-9 — Request for Taxpayer Identification Number and Certification.
The information provided on Form W-9 helps the payer prepare Forms 1099 and determine whether backup withholding may be required.
Why Form W-9 Matters Before You Pay a Contractor
Form W-9 is one of the most important documents in contractor onboarding.
A properly completed W-9 normally gives the business:
- Legal name
- Business name, when applicable
- Federal tax classification
- Address
- Taxpayer identification number
- Required certifications
The IRS states that a properly completed and signed Form W-9 can generally be relied upon to avoid backup withholding when the applicable requirements are satisfied.
This is why collecting W-9 information before payments begin is a much better practice than chasing contractors for tax information months later.
Consider two businesses.
Business A hires a consultant and obtains a completed Form W-9 during onboarding.
Business B hires the same type of consultant but pays invoices for several months without ever collecting the tax information.
Business B is creating unnecessary risk.
If the consultant later fails to provide a valid TIN, the business may have to deal with backup withholding, incorrect information returns, IRS notices and additional administrative work.
Missing TIN vs. Incorrect TIN
These situations are related but not identical.
Missing TIN
A TIN can be considered missing when the payee does not provide it or when the number is obviously invalid.
IRS Publication 1281 gives examples such as numbers containing the wrong number of digits or certain obviously incorrect formats.
When a payer is making reportable payments and does not have the required TIN, backup withholding may need to begin.
Incorrect TIN
A TIN may appear correctly formatted but still fail to match IRS records.
For example:
Name: John Smith Consulting LLC
EIN: 12-3456789
The number may contain the correct number of digits, but the name/TIN combination submitted on the information return might not match IRS records.
That type of mismatch can result in an IRS notice.
What Are CP2100 and CP2100A Notices?
When a payer files information returns containing missing or incorrect taxpayer identification information, the IRS may send:
CP2100
or
CP2100A
These notices tell the payer that one or more names and taxpayer identification numbers reported on information returns do not match IRS records or otherwise contain problems.
The IRS generally issues CP2100 when the payer’s error listing contains 50 or more information returns.
CP2100A is generally used when the payer has fewer than 50 information returns with errors.
The substantive instructions are otherwise the same.
What Should a Business Do After Receiving a CP2100 Notice?
Do not ignore it.
The business should compare the IRS listing against its own records and determine what action is required for each affected payee.
Depending on the situation, the payer may need to:
- Correct internal records.
- Request updated information.
- Send the appropriate notice to the payee.
- Obtain a new Form W-9.
- Begin backup withholding.
- Continue withholding until applicable requirements are satisfied.
IRS Publication 1281 provides procedures for responding to missing and incorrect name/TIN combinations.
What Is a “B” Notice?
The term B Notice is commonly associated with the IRS backup-withholding program involving missing or incorrect taxpayer identification information.
When appropriate, the payer sends a notice to the affected payee asking them to correct or certify their taxpayer information.
The specific process depends on the circumstances and whether this is the first or a later mismatch involving the same account.
The IRS’s 2026 General Instructions for Certain Information Returns explain that payers receiving an incorrect-TIN notice may be required to promptly furnish a B Notice or acceptable substitute to the payee and follow Publication 1281 procedures.
This is another reason businesses need organized vendor records.
If a company cannot locate the contractor’s W-9, payment history or contact details, responding properly becomes more difficult.
Example: Contractor Does Not Provide a TIN
Imagine a small company hires an independent photographer.
The photographer invoices:
$1,500
but repeatedly refuses to provide the taxpayer identification information necessary for the company’s reporting obligations.
If backup withholding applies, the payer may be required to withhold:
24% × $1,500 = $360
The photographer would receive:
$1,140
and the payer would generally be responsible for handling the $360 as federal backup withholding.
This does not mean the business keeps the money.
The withholding must be handled under the applicable federal deposit and reporting rules.
What Payments Can Be Subject to Backup Withholding?
Backup withholding can apply to a variety of information-reportable payments.
Depending on the circumstances, these may include payments reported on forms such as:
- Form 1099-NEC
- Form 1099-MISC
- Form 1099-INT
- Form 1099-DIV
- Form 1099-K
- Form 1099-B
- Form 1099-OID
- Certain other information returns
The IRS’s backup-withholding guidance lists multiple information-return categories that can be affected.
For many small businesses, the contractor-payment context involving Form 1099-NEC is one of the most relevant.
Backup Withholding and Form 1099-NEC
Suppose a business makes reportable nonemployee-compensation payments to a contractor.
Ordinarily, the business pays the contractor without federal income-tax withholding.
But if backup withholding becomes required, the business may have to deduct 24% from future reportable payments.
The business must then correctly report both:
- the payment, and
- the federal income tax withheld.
An especially important IRS rule is that when backup withholding occurs, the payment may need to be reported on the appropriate information return even when the payment is below the amount that would normally trigger information reporting.
Businesses therefore should not assume:
“The payment was small, so we can ignore the backup withholding.”
Where Is Backup Withholding Reported?
Payers generally report backup withholding using:
Form 945 — Annual Return of Withheld Federal Income Tax.
The IRS states that Form 945 is used to report backup withholding and certain other nonpayroll federal income-tax withholding.
This is separate from ordinary employee payroll reporting.
A business should therefore avoid casually mixing contractor backup withholding into regular employee payroll records without understanding the reporting requirements.
The Payee Can Usually Claim Credit for Backup Withholding
Backup withholding is not necessarily an additional permanent tax on top of everything else the payee owes.
It is federal income tax withheld in advance.
If a contractor receives a Form 1099 showing federal income tax withheld under the backup-withholding rules, the IRS states that the contractor generally reports that amount as federal income tax withheld on their own income tax return.
The final tax result depends on the taxpayer’s overall return.
For example:
A contractor has $2,000 withheld through backup withholding during the year.
When completing the federal income tax return, the contractor calculates total federal tax liability of $5,000.
That $2,000 withholding may generally be applied as tax already paid, leaving the remaining amount subject to the taxpayer’s full circumstances.
What If the Contractor Corrects the TIN?
Backup withholding does not necessarily continue forever.
If the issue involves an incorrect taxpayer identification number, the payee may be able to stop or prevent backup withholding by providing the correct name/TIN combination and completing the required certification.
The IRS explains that a payee receiving an initial incorrect-TIN notice can generally address the problem by providing the payer with correct information and certifying it appropriately.
Different requirements can apply after repeated notices.
Businesses should follow the specific IRS notice instructions rather than simply deciding on their own that the issue has been corrected.
Common Business Mistakes With Backup Withholding
Waiting Until January to Collect W-9 Forms
Businesses sometimes wait until they are preparing Forms 1099 before asking contractors for W-9 information.
That is too late.
Collect tax information during onboarding.
Assuming an Email With a TIN Is Enough
Businesses should maintain proper W-9 documentation rather than relying on an informal email containing a number.
Ignoring Name/TIN Mismatch Notices
A CP2100 or CP2100A notice requires attention.
Ignoring it can increase tax and penalty exposure.
Continuing to Pay the Full Amount When Withholding Is Required
Once backup withholding is required, simply continuing normal payments can create liability for the payer.
The IRS warns that payers may be responsible for backup withholding they failed to deduct when required.
Treating Backup Withholding as a Business Fee
The 24% amount is federal tax withholding.
It is not a penalty that the business keeps and it is not a service fee.
Confusing Backup Withholding With Employee Payroll Tax
Contractor backup withholding should not be confused with ordinary employee payroll withholding.
Different rules and reporting mechanisms apply.
Case Study: A Business Receives an IRS TIN Mismatch Notice
Consider a marketing company that works with 75 freelancers and service providers.
The company collects vendor information inconsistently.
Some contractors completed Form W-9.
Others simply emailed their tax IDs.
Several vendor records use business names that do not match the legal names connected to the reported taxpayer identification numbers.
The company eventually files its information returns.
Months later, it receives an IRS CP2100 notice identifying several incorrect name/TIN combinations.
Instead of ignoring the notice, the finance manager:
- Compares each IRS-listed account with company records.
- Identifies which information came from proper W-9 forms.
- Contacts affected vendors according to the required procedures.
- Obtains corrected information where appropriate.
- Begins backup withholding where required.
- Creates a formal vendor onboarding checklist for future contractors.
The company then changes its policy:
No reportable vendor begins normal payment processing until the required tax-information documentation has been collected and reviewed.
That administrative improvement reduces the likelihood of repeating the same problem the following year.
A Better Vendor Onboarding Process
Businesses can reduce backup-withholding problems by building tax compliance into vendor onboarding.
A practical process may include:
Step 1: Collect Form W-9 Before Payment
Obtain the contractor’s tax information before the first reportable payment whenever possible.
Step 2: Review the Form
Check for:
- Missing legal name
- Missing tax classification
- Missing TIN
- Obvious formatting problems
- Missing signature where required
- Inconsistent business information
Step 3: Store the W-9 Securely
Taxpayer identification numbers are sensitive information.
Businesses should restrict access and use appropriate data-security controls.
Step 4: Match Vendor Records Consistently
The accounting system should use the appropriate legal/payee information rather than casually changing names across invoices and payment records.
Step 5: Monitor IRS Notices
Make sure CP2100, CP2100A and similar correspondence reaches the person responsible for information reporting.
Step 6: Document Corrections
Maintain records of new W-9 forms, correspondence and backup-withholding actions.
Should Businesses Verify TINs Before Filing?
Businesses that file significant volumes of information returns may consider IRS TIN-matching resources where eligible.
TIN matching can help identify certain name/TIN inconsistencies before information returns are filed.
However, access rules and procedures apply, and businesses should use official IRS systems appropriately.
Even when TIN matching is used, proper Form W-9 collection and recordkeeping remain important.
Backup Withholding Is Not the Same as Foreign-Person Withholding
Businesses working internationally need to be especially careful.
The 24% backup-withholding rules described here generally concern U.S. persons subject to information reporting.
Foreign persons can be subject to completely different withholding regimes, documentation rules and tax rates.
For example, the IRS notes that Chapter 3 and Chapter 4 withholding involving non-U.S. persons differs from Section 3406 backup withholding.
Businesses making payments to foreign individuals or entities should not simply apply the domestic W-9/backup-withholding framework without reviewing the appropriate international-tax documentation.
Frequently Asked Questions About Backup Withholding
What is backup withholding?
Backup withholding is federal tax withholding required on certain reportable payments when specified conditions exist, such as a missing or incorrect taxpayer identification number.
What is the current backup withholding rate?
The current federal backup-withholding rate is 24%.
Does every independent contractor have 24% withheld?
No.
Independent contractors generally receive payments without federal income-tax withholding. Backup withholding applies only when the relevant statutory conditions exist.
Can a missing W-9 cause backup withholding?
A missing W-9 is important because the payer may lack the required certified taxpayer identification information. Depending on the payment and circumstances, missing TIN information can require backup withholding.
What happens if the IRS says a contractor’s TIN is incorrect?
The payer should follow the IRS notice procedures, update records as required, send applicable notices to the payee and begin or continue backup withholding when required.
What is CP2100A?
CP2100A is an IRS notice concerning information returns with missing or incorrect name/TIN information. The IRS generally uses CP2100A when fewer than 50 information returns are included in the error listing.
What form reports backup withholding?
Payers generally report backup withholding on Form 945, Annual Return of Withheld Federal Income Tax.
Can the contractor get credit for the tax withheld?
Generally, yes. The payee normally reports backup withholding shown on the information return as federal income tax withheld on their tax return.
Does backup withholding stop after a corrected W-9 is received?
It may, depending on why withholding began and whether the required correction and certification procedures have been satisfied. Businesses should follow the applicable IRS instructions rather than stopping withholding prematurely.
How PhcWorkhub Can Help Businesses Organize Contractor Tax Records
Backup withholding is a good example of why contractor documentation needs to be organized before tax season.
Businesses dealing with independent contractors may need to manage:
- Form W-9 information
- Contractor names and addresses
- Taxpayer identification details
- Payment records
- 1099 reporting
- Vendor agreements
- IRS correspondence
- Corrected tax information
- Backup-withholding records
PhcWorkhub provides business-document and tax-form tools designed to help businesses and independent professionals keep important financial documentation more organized.
Good document organization does not replace professional tax advice, but it can reduce the confusion that occurs when W-9 information, payment history and contractor records are scattered across emails, spreadsheets and accounting systems.
Final Thoughts: Collect Correct Tax Information Before Payments Begin
Backup withholding is one of those tax rules many small businesses do not think about until an IRS notice arrives.
The basic lesson is straightforward:
Collect correct contractor tax information early.
Form W-9 helps businesses obtain the legal name, taxpayer identification number and certifications needed for information reporting.
When a TIN is missing, incorrect or subject to an IRS backup-withholding notice, a business may be required to withhold 24% from certain reportable payments and report that withholding properly.
Businesses should also take CP2100 and CP2100A notices seriously, maintain accurate vendor records and understand that failing to withhold when required can create liability for the payer.
A strong process is therefore:
Collect → Verify → Record → Pay → Report → Correct when necessary.
For contractors, providing an accurate Form W-9 promptly can help prevent unnecessary backup withholding and ensure that information returns are prepared using the correct taxpayer details.
For businesses, good onboarding and accurate tax-document management can prevent a small vendor-record problem from becoming a much larger compliance issue.
PhcWorkhub helps businesses and independent professionals organize the forms, payment records and business documents needed to support clearer financial operations throughout the year.
Disclaimer: This article provides general educational information and is not individualized tax, accounting or legal advice. Backup-withholding requirements depend on the payment, taxpayer status, IRS notices and other facts. Businesses and payees should consult current IRS guidance or a qualified tax professional for specific situations.
