What Is an IRS CP2000 Notice — and What Should You Do About It?
A CP2000 notice tends to arrive with a jolt: an official IRS letter proposing that you owe more money. Before you panic, it helps to understand exactly what a CP2000 is — and, just as importantly, what it isn’t.
What a CP2000 actually is
A CP2000 is an underreporter notice. It’s generated automatically when the income reported on your tax return doesn’t match the information the IRS received from third parties — an employer’s W-2, a bank’s 1099-INT, a brokerage’s 1099-B, and so on.
It is not an audit. It is not a final bill. It’s a proposal — the IRS is saying, “based on what others reported, your numbers look off by this much; do you agree?”
Why you got one
Common triggers include a 1099 you forgot about, a stock sale where the cost basis wasn’t reported, freelance income that slipped through, or a simple mismatch in how something was categorized. Sometimes the IRS is right. Sometimes the third-party data is wrong or incomplete, and the proposed change is overstated.
How to respond
The notice includes a response deadline — usually 30 days — and a form to indicate whether you agree or disagree.
- If you agree, you sign and return the response, and arrange to pay or set up a payment plan.
- If you disagree, you respond with an explanation and documentation supporting your original numbers.
- If you partially agree, you can accept some adjustments and contest others.
The one thing you should never do is ignore it. If you don’t respond by the deadline, the IRS typically issues a Notice of Deficiency and the proposed amount becomes an assessed balance — much harder to unwind.
Catching it in time
The hardest part of a CP2000 is often just knowing it exists while there’s still time to respond well. Notices sit in mailboxes; deadlines run quietly in the background. TaxRock watches your IRS account continuously and flags a CP2000 the moment it posts — with the response deadline already calculated — so a routine mismatch never turns into an assessed balance simply because a letter got buried.