Understanding a CP2000 Notice (And How to Respond)

A client forwards you a CP2000 notice, usually in a panic, usually with a subject line like "IRS AUDIT???" Here's what to tell them first: it's not an audit. It's an automated letter, and once you know what triggered it, responding is usually a straightforward, if slightly tedious, process.

What a CP2000 actually is

A CP2000 is generated automatically when the IRS's computer system matches the income reported on a client's tax return against the income reported to the IRS by third parties, like a W-2 from an employer, a 1099 from a client or brokerage, or interest income from a bank, and finds a mismatch. No IRS employee has personally reviewed the return before this notice goes out. It's purely a computer-matching process, which is exactly why it's so common: a single missed 1099 or a brokerage statement that arrived after the return was filed is enough to trigger one.

Why "it's not an audit" is worth saying clearly to a client

Clients hear "IRS notice" and assume the worst. A CP2000 doesn't mean they're being investigated, and it doesn't mean they did anything wrong on purpose. It means one number on their return doesn't match a number the IRS received from someone else, and the IRS is proposing a change based on that mismatch. Setting that expectation early, before walking through the actual numbers, does more to calm a client down than anything else you'll say in that first conversation.

The three things you're actually checking

1. Is the IRS's information correct? Sometimes it is. A 1099 got left off the original return by mistake, and the proposed change is accurate.
2. Is the IRS's information wrong or duplicated? This happens more than people expect, especially with brokerage accounts that report the same transaction under slightly different names, or income that was already reported correctly under a different line item.
3. Is there an offsetting deduction or basis the IRS doesn't know about? A very common scenario with stock sales: the IRS sees the full sale proceeds reported on a 1099-B but doesn't know the cost basis, so it proposes tax on the entire sale amount rather than just the gain. This is one of the single most common reasons a CP2000 overstates what's actually owed.

How to actually respond

The notice includes a response form with two boxes: agree, or disagree (partially or fully). If the client agrees, sign and return the response with payment or a payment plan request. If they disagree, in whole or in part, you'll need to write a clear explanation and attach documentation supporting the correct number, things like a corrected 1099, a brokerage statement showing cost basis, or an amended schedule. The IRS gives a response deadline, typically 30 days from the notice date, and missing it can result in the proposed changes being assessed automatically, so this isn't something to let sit in a to-do list.

What clients get wrong on their own

Left to handle it themselves, a lot of clients either panic-pay the full proposed amount without checking whether it's actually correct, or ignore the notice entirely because it's confusing, which is worse. Both outcomes cost more than a proper response would. This is squarely the kind of situation where a client benefits from having someone review the notice against the actual return before deciding how to respond, rather than reacting to the number at the top of the letter.

Before you can even look at it

If you weren't the preparer of record or don't already have representation authorization on file, you'll need a signed Form 2848 before you can discuss the notice with the IRS directly, or a signed Form 8821 if you just need to pull the client's transcripts to check the numbers first. Getting that signed and filed is the first practical step, not an afterthought, since it's the thing that determines how fast you can actually move once you've reviewed the notice.