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Form W-9, TIN, and 24% Backup Withholding

October 17, 2026 · Guide 5 of 16 · 3 min read

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Educational information only. Not tax, legal, or financial advice. 1099-NEC Filing is not the IRS and is not affiliated with it. Check IRS.gov and consider a qualified tax professional. Last checked against the cited sources: October 17, 2026. Anything marked expected for 2027 should be re-checked. Examples use made-up numbers.

Short answer: The IRS says backup withholding is a tax the payer must withhold, at the current rate of 24%, in certain situations. One example is a payee who does not give a correct taxpayer identification number (TIN). A TIN can be an SSN, an EIN, or an ITIN. The IRS says you may give the payee Form W-9 to provide the TIN and to certify it under penalties of perjury.

Why this matters for Form 1099-NEC

  • Collect the W-9 before the first payment. It is also where you get the name and address for the information return.
  • If you withhold federal income tax under backup withholding, you must file a 1099-NEC for that person regardless of the payment amount, with the withheld amount in box 4.
  • The IRS says backup withholding can apply to commissions, fees, and other payments for independent contractor work reported on Form 1099-NEC.

The checker treats “federal income tax withheld: yes” as a reason to file, at any amount. If you mark “TIN received: no,” it does not decide that you must withhold. It flags the row so you can read the IRS backup withholding page.

When it stops

Per the IRS, backup withholding stops when the reason is corrected. Providing the correct TIN is the example the page gives.

What you do with the withheld money

Payers deposit withheld amounts with the IRS under separate rules (Form 945 and its deposit schedules). those deposit rules were not verified for this guide.

Attorneys

The instructions say an attorney must supply its TIN even if it is a corporation, but is not required to certify that TIN. If the attorney does not give you a TIN, you must backup withhold.

Practical tips, not advice

  • Keep W-9 files secure. They contain sensitive data. Do not share them or publish them.
  • Do not put a TIN in a spreadsheet that many people can open.
  • the IRS instructions mention a TIN Matching system. Availability was not checked for this page.

FAQ

Do I send Form W-9 to the IRS?

common practice is that the requester keeps the form. The W-9 form instructions were not read for this sentence. Do not mail a stack of W-9s to the IRS because a blog told you to, and do not assume this page replaces the form instructions.

Is 24% fixed forever?

The IRS page calls 24% the “current rate.” That is the rate this site uses. If the IRS changes the page, this sentence needs a new reading.

What we could not verify

  • Deposit timing and Form 945 reporting of withheld amounts.
  • The “do not send the W-9 to the IRS” statement, which was not read in the form instructions.
  • Publication 1099 (general instructions) was not read. The inflation-adjusted threshold for payments made after 2026 is not published, and no number for 2027 is stated here.
  • State filing rules vary and are not covered. Many states have their own requirements.
  • Worker classification (employee versus contractor) is not decided here. See IRS guidance and consider a qualified professional.

Sources

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