IRS Letters and Forms
CP21B

CP21B — Notice of Data Processing adjustments resulting in an overpayment of $1.00 or more.

Notice of Data Processing adjustments resulting in an overpayment of $1.00 or more.

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CP21B

Read the notice carefully and note any deadline. Gather returns, notices, and payment records. Book a free strategy session before responding if the amount is large, unclear, or collection language appears.

What the IRS language says

Notice of Data Processing adjustments resulting in an overpayment of $1.00 or more.

What it usually means

CP21B is in our IR Manual catalog. Official wording is dense — we translate it for business owners and individuals and map realistic next steps.

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