IRS CP2000 Notice: Underreporter Inquiry — How to Respond

The CP2000 is issued by the IRS Automated Underreporter (AUR) program when income reported to the IRS on 1099s, W-2s, or other information returns does not match what was reported on your tax return. The IRS proposes changes to your tax and calculates a new balance due, including penalties and interest. It is not a bill — it is a proposal that requires your response.

Common reasons include: a 1099 was issued in your name but the income was not reported; a 1099 was double-counted; the IRS did not see offsetting deductions or cost basis; you received a 1099-K for gross payment processing but your net income was much lower; or a brokerage reported proceeds without the correct cost basis. Many CP2000 proposed balances are incorrect or overstated.

Many taxpayers panic when they receive a CP2000 because they think they are being audited. The CP2000 process is handled by the Automated Underreporter Unit and is a correspondence process, not a full examination. You respond by mail with supporting documentation — there is no in-person audit unless the case is escalated.

You have three options: agree and pay the proposed amount; partially agree and provide documentation for the items you dispute; or fully disagree and provide documentation showing the IRS's information is incorrect. You must respond by the deadline on the notice (typically 60 days). Submit your response with supporting documents — bank statements, 1099s with cost basis, contracts, receipts — anything that supports your position.

Do not automatically pay the proposed amount without reviewing it. Many CP2000 notices are significantly reduced once proper deductions are documented. Do not ignore it — a CP2000 that goes unanswered becomes an assessment 90 days later. Do not send only a letter — always include documentation. And do not confuse the gross amount on a 1099-K with your actual income.

A freelance graphic designer in Burbank received a CP2000 proposing $8,400 in additional tax. The IRS had received 1099-NEC forms totaling $41,000 but saw no business expenses on his return because he had filed a standard return without a Schedule C. We responded with a Schedule C showing $26,000 in legitimate business expenses, reducing the proposed balance to $1,900 — a savings of over $6,500.