A CP2000 is not a bill and not an audit — it is the IRS proposing changes to your return because a third-party form (a W-2, 1099, or K-1) does not match what you reported. The proposed balance is a computer’s opinion. It is frequently wrong — especially on stock sales reported without basis, where the IRS’s match treats the entire proceeds as gain.
By Sam Brotman, JD, LLM, MBA · Last updated August 2026
Your deadline
30 days from the notice date to respond — agree, disagree with documentation, or partially agree. Respond in writing, keep proof of mailing, and do not simply pay a number you have not verified.
What happens if you ignore it
The IRS assesses the proposed amount, adds accuracy-related penalties where they apply, and issues a Notice of Deficiency — the 90-day letter that forces the dispute into Tax Court or concedes it. A disagreement that could have been resolved with one brokerage statement becomes a formal proceeding.
Your options
Match the notice line-by-line against your records. Missing basis on stock or crypto sales, income reported twice, a 1099 that belongs to someone else, or income properly reported on a different line resolve most CP2000s in the taxpayer’s favor — partially or entirely. If the notice is right, penalties may still be wrong: reasonable-cause and first-time abatement apply here too.
What we do
We reconstruct the mismatch, respond with the documentation that closes it, and contest the penalties separately. CP2000s are winnable letters — the machine that sends them does not read brokerage statements, and we do.
Holding this notice now? Book a free 15-minute call or call (619) 378-3138. We will tell you exactly where you are in the collection process and what your options are before you spend anything. Our IRS collections attorney team handles these matters statewide.