IRS Letter 2800C: Withholding Lock-In Letter for Employers
The IRS is directing you, as the employer, to withhold income tax from an employee's wages at the rate in the letter, starting 60 days from the letter date.
Numbers covered by this guide
Letter 2800C
Ltr 2800C
Check the identifier and follow the instructions on your own notice.
Published by the Law Offices of Darrin T. Mish, P.A.•Updated February 26, 2026
General information only, not legal advice. Using this page does not create an attorney-client relationship. This information may be incomplete or out of date and is provided without any guarantee; follow the instructions and deadline on your own notice. Full terms and disclaimer
Notice
Letter 2800C / Ltr 2800C
Urgency
Urgent
Deadline
Start the new withholding 60 days from the letter date
Your first move
Begin withholding at the rate in the letter for this employee, effective 60 days from the letter date, and give the employee their copy.
Deadline calculator
Estimate your Letter 2800C deadline
Estimate only. If your notice shows a specific respond-by date, that date controls. Some deadlines run from the mailing date, and a statewide holiday where the IRS office is located can also extend a deadline. Mail early, keep proof of mailing, and if a deadline matters, have a professional confirm it. Terms and disclaimer
See it explained
Letter 2800C in plain English
Letter 2800C: what it means, in 30 secondsA 30-second overview from tax attorney Darrin T. Mish: what this notice is, the deadline, and your first move.
What This Letter Means
Letter 2800C goes to employers. The IRS believes one of your employees filed an incorrect Form W-4 and isn't having enough federal income tax withheld. This is a "lock-in" letter. It sets the withholding status and maximum number of withholding allowances you must use for that employee, often single with zero allowances.
It is not a bill, and it isn't about your own account.
What to Do
Begin withholding from the employee's wages at the rate in the letter, effective 60 days from the date of the letter, unless the IRS tells you otherwise.
Give the employee the copy of the letter that is included for them.
If the employee no longer works for you, you don't need to do anything. If they return to work within 12 months, start withholding at the rate in the letter.
After the Lock-In Takes Effect
Disregard any new Form W-4 from the employee that decreases withholding.
If the employee submits a Form W-4 that claims fewer allowances than the maximum in the letter, increase withholding based on that form.
Block the employee from using any online W-4 system to decrease their withholding.
To get a decrease, the employee must send a new Form W-4 and a supporting statement to the IRS, not to you. The IRS will notify you if it approves the change.
Modification Letters
If you later receive Letter 2808C, a modification letter from the Withholding Compliance Program, the changes to marital status or allowances take effect immediately. You don't wait another 60 days.
Questions
Contact the IRS Withholding Compliance Unit using the information on the letter. Keep a copy of the letter in the employee's payroll file.
If you received Letter 2800C and have questions about your withholding obligations, call us at (813) 229-7100.
This letter has a clock on it. Don’t run it out alone.
Free consultation with Darrin T. Mish, a Tampa tax attorney licensed since 1993 and admitted to the U.S. Tax Court. Bring the letter.