What CP136 / Form 945 deposit notices is
Notices about your nonpayroll withholding account: which deposit schedule applies for the coming year (based on the lookback period), missing Form 945, or deposits that don't match the return.
Where this sits: these notices come from the Form 945 side of the house, the return on which backup withholding is reported and deposited. The Form 945 page covers the account mechanics behind them.
The deadline
Per the notice; a missing-945 notice typically gives 30 days.
What to do
Reconcile backup withholding withheld, deposited and reported; file or correct Form 945; adjust the deposit schedule if the notice changes it.
How the Form 945 deposit schedule is set
CP136 is the annual notice that tells a Form 945 filer which deposit schedule applies for the coming calendar year. The IRS sets it from the lookback period, which for Form 945 is the second calendar year before the year in question: the schedule for 2027 depends on the total tax reported on the 2025 Form 945. A payer whose lookback total was $50,000 or less is a monthly depositor, due on the 15th of the following month; above $50,000 the payer is a semiweekly depositor, with Wednesday and Friday deposit days depending on when the withholding happened. Two rules cut across the schedule in either direction. A payer whose total Form 945 liability for the year is under $2,500 may pay it with the return instead of depositing, and any single day on which accumulated liability reaches $100,000 triggers a deposit by the next business day regardless of schedule.
Backup withholding is reported on Form 945, not Form 941, and the two accounts have separate lookback periods and separate schedules. A payer that is semiweekly for payroll can be monthly for Form 945, and often is.
The other Form 945 notices
The same account produces a missing-return notice when the IRS has withholding reported on Forms 1099 (box 4) or W-2G and no Form 945 for the year, and a balance or credit notice when the deposits posted do not match the liability on the return. For a semiweekly depositor the mismatch is usually a Form 945-A problem (the record of daily liability was not attached, or does not add to the return), which the Form 945 page explains. The deposit penalty calculator shows what a late or short deposit costs under the 2, 5, 10 and 15 percent tiers of IRC 6656, and CP 236 is the reminder that goes to a payer who has just become semiweekly and missed the first deposit.
Questions about CP136 / Form 945 deposit notices
Who receives CP136 / Form 945 deposit notices?
Payer. Notices about your nonpayroll withholding account: which deposit schedule applies for the coming year (based on the lookback period), missing Form 945, or deposits that don't match the return.
What is the deadline on CP136 / Form 945 deposit notices?
Per the notice; a missing-945 notice typically gives 30 days.
What should I do when CP136 / Form 945 deposit notices arrives?
Reconcile backup withholding withheld, deposited and reported; file or correct Form 945; adjust the deposit schedule if the notice changes it.
Is CP136 / Form 945 deposit notices about my own income tax?
No. This decoder covers information reporting and withholding: the notices a payer, filer or payee sees because of Forms 1099, W-2, 945 and the TINs on them. Individual income-tax notices follow a different track.
Have a different notice? The IRS notice decoder lists all 77 in the order they tend to arrive.