Child Tax Credit: How To Win a CTC or Form 8332 Dispute in Tax Court

The IRS denied your Child Tax Credit. Maybe a letter says someone else already claimed your child. Maybe the refund you were counting on—part of it built from that credit—got clawed back, and now you owe money you already spent. Maybe a notice changed your numbers without ever asking you a question.

You are not the first person this happened to, and it is one of the more winnable fights a taxpayer can have with the IRS. The credit was almost never denied because you are ineligible. It was denied because the IRS could not see proof that the child is yours and lived with you—or because two returns claimed the same Social Security number and the IRS has to sort out who wins. The fix is proof, the right documents for the right year, and knowing which deadline you are actually staring at.

Here is the reassuring part first: US Tax Court is a prepayment forum. If your dispute reaches a Notice of Deficiency, you do not have to pay the tax before you fight it—you file a petition and the assessment is put on hold while a judge looks at your evidence. But there is a catch that is brand new and easy to miss. Some Child Tax Credit denials—specifically the ones tied to a missing or wrong Social Security number—now arrive as a math-error notice, not as a 90-day letter, and that path has a different, shorter clock. We will get to that, because if you are holding one of those, the deadline matters more than anything else in this article.

This guide is the companion to How To Prove Your EITC and Dependent Claims to the IRS. That article owns the Earned Income Tax Credit and the deep residency-proof playbook. This one owns the Child Tax Credit itself: the dollar amounts, the refundable piece, the age-17 trap, the new SSN rules, the "someone else claimed my child" (CP87A) fight, and Form 8332. Where the two overlap, we will keep it short here and point you there.

The Big Change for 2025: $2,200, Permanent, and a New SSN Rule

The Child Tax Credit lives in IRC § 24. In July 2025, the One Big Beautiful Bill Act—Public Law 119-21—rewrote the most important parts of it. Three changes matter to you:

• The credit is now $2,200 per qualifying child for 2025, up from $2,000. ("Qualifying child" is a defined term—the five § 152(c) tests below, not just "a kid who qualifies.") The law struck "$2,000" out of the statute and inserted "$2,200."
• It is permanent. The old law was set to expire at the end of 2025 and snap back to $1,000 per child. That sunset was deleted. The $2,200 amount is also indexed for inflation for years after 2025, rounded down to the next lowest $100, so it will creep up over time.
• There is a new Social Security number requirement on the taxpayer, not just the child. Starting with 2025 returns, the person claiming the credit must have a work-eligible SSN (on a joint return, at least one spouse must have one). And—this is the procedural trap—a missing or wrong SSN anywhere in § 24 is now treated as a "math error," which lets the IRS adjust your return without sending you a Notice of Deficiency at all.

Those figures are the law as enacted, confirmed against the bill text and the current IRS Schedule 8812 instructions. Do not round them or guess—use the exact amount for the year under audit.

And that last point is the key one: most Child Tax Credit disputes are not about this year's return. The IRS audits on a lag, so a notice arriving in 2026 is often about a 2022, 2023, or 2024 return. The rules that apply to your case are the rules for the year under examination, not the current year. Here is the amount per qualifying child by year:

If your dispute is about a 2021 return, treat it as the odd one out—the fully refundable, advance-payment, age-under-18 rules were a one-year regime that vanished in 2022. For every other year, the structure below applies.

What the Credit Actually Is: CTC, ACTC, and the $500 ODC

Before you fight over the credit, it helps to know what the IRS took—because part of it is real cash, and part of it is just a reduction in tax you owe. The difference decides whether a denial means you "lose a discount" or whether you have to write the IRS a check.

A credit is nonrefundable when it can only reduce your tax to zero—if you owed $800 in tax and had a $2,200 credit, the credit wipes out the $800 and the other $1,400 just disappears. A credit is refundable when the leftover comes back to you as a refund—that same $1,400 lands in your bank account. The Child Tax Credit is a hybrid of both.

The nonrefundable Child Tax Credit (§ 24(a)). Up to $2,200 per qualifying child (2025), applied first against the tax you owe.

The refundable Additional Child Tax Credit, or ACTC (§ 24(d)). When the credit is bigger than your tax bill, this is the piece that comes back as a refund. It is 15% of your earned income above $2,500, capped at $1,700 per child (2024 and 2025). So a low-income parent with little tax liability gets most of the benefit not as a tax reduction but as a refund check.

That is exactly why a Child Tax Credit denial can feel like a punch. If the IRS already paid you the refund and then disallows the credit, the refundable portion is money you have to pay back—a clawback. You are not losing a future deduction; you are repaying cash that is already gone. For a parent of two who got the full refundable amount, that can be $3,400 back to the IRS before penalties or interest.

The $500 Credit for Other Dependents, or ODC (§ 24(h)(4)). This is a $500 nonrefundable credit for a dependent who is not a CTC-qualifying child—a 17- or 18-year-old, an older student, a parent you support. Unlike the Child Tax Credit, the ODC dependent can have an ITIN (Individual Taxpayer Identification Number, the number the IRS issues to people who can't get an SSN) instead of a Social Security number. The ODC was also made permanent by the 2025 law.

One more timing rule worth knowing: by law, the IRS cannot release a refund that includes the ACTC before mid-February, even if you filed in January. That hold (a fraud-screening measure that is still on the books) is normal and is not a sign your claim is in trouble.

The Age-17 Trap and the Other CTC Tests

The single most common honest mistake on the Child Tax Credit is age. For the CTC, the child must be under 17 at the end of the tax year (§ 24(c)). Not under 18, not under 19—under 17.

This is the "age-17 trap." A 16-year-old who turns 17 on December 30 is too old for the Child Tax Credit for that entire year, even though they are still your dependent and—if under 19—still count for the Earned Income Tax Credit. The IRS's own dependent worksheet says it outright: that child does not qualify for the CTC, though they may qualify for the $500 ODC instead. So if a notice denied the credit for your teenager, check their birthday before you fight—you may have an ODC claim rather than a CTC claim, and conceding the wrong piece gracefully is faster than losing it loudly.

Beyond age, a CTC-qualifying child has to pass the same five tests as a qualifying child for the EITC, under IRC § 152(c):

• Relationship — your son, daughter, or their descendant (a grandchild), or your sibling, step-sibling, or their descendant (a niece or nephew). Adopted and eligible foster children count.
• Age — for the CTC specifically, under 17 at year-end (the trap above).
• Residency — the child lived with you for more than half the year. This is the single most-contested element in these cases.
• Support — the child did not provide more than half of their own support.
• Joint return — the child did not file a joint return with a spouse (except solely to claim a refund).
• Citizenship and SSN — the child must be a US citizen, national, or resident, and have a work-eligible Social Security number issued by the return due date.

We are not going to re-teach those five tests in depth here, because the EITC and dependent-claims guide already walks through each one and—crucially—through exactly how you prove residency with paper. Residency is where most of these cases are actually won or lost, and that guide is the place to learn it. What is unique to the Child Tax Credit is the under-17 age line and the SSN rules, which are strict enough to deserve their own section.

The SSN Rules and the Math-Error Trap

The Social Security number rules are where the Child Tax Credit catches families that are otherwise completely eligible. They are also where the brand-new procedural trap lives.

The child's SSN. To claim the CTC for a child, that child must have a work-eligible Social Security number issued before the due date of the return (§ 24(h)(7)). An SSN that came through a week after the deadline does not count for that year—even if the child is yours and lived with you all year. (The $500 ODC is more forgiving: it accepts an ITIN or adoption taxpayer ID number, not just an SSN.)

A baby born any time in the year qualifies for the full year. A child born at any point in the year—even December—gets the full year's Child Tax Credit, as long as the child has a work-eligible SSN by your return's due date. Apply for the newborn's SSN right away; if it won't arrive in time, talk to a tax professional or LITC about your options (such as the $500 ODC) before the deadline rather than missing it.

The new taxpayer's SSN (2025 forward). Starting with 2025 returns, the 2025 law added a requirement that you—the person claiming the credit—also have a work-eligible SSN. On a joint return, at least one spouse must have one. Before this change, only the child's number was checked. This rule applies to tax years beginning after December 31, 2024, so for a 2021–2024 return only the child's SSN mattered.

If you file with an ITIN (so the new taxpayer-SSN rule blocks your CTC for 2025 onward), the $500 Credit for Other Dependents still accepts an ITIN and may still be available; an LITC can help with the immigration overlay.

Now the trap. The same 2025 law amended the math-error rules in IRC § 6213(g) so that a missing or incorrect Social Security number anywhere in § 24 is a "mathematical or clerical error." In plain English: a math error is a category of mistake the IRS is allowed to fix on your return and assess the extra tax without sending you a Notice of Deficiency first—no 90-day letter, no automatic ticket to Tax Court. The notice you get (often a CP11 or CP12) just tells you the IRS already changed your numbers.

This is a different fight with a different clock. When the IRS makes a math-error adjustment, you have 60 days from the date of the notice to request that the IRS abate (cancel) it. "Abatement" here just means asking the IRS to undo the summary adjustment. If you ask within those 60 days, the IRS must remove the assessment and—if it still wants the money—come back through the normal deficiency process, which does give you a Notice of Deficiency and the right to petition Tax Court before paying. If you miss the 60 days, the assessment stands, and you are pushed into slower channels: a refund claim or audit reconsideration.

So the practical rule: if your CTC denial came as a math-error notice (it adjusted your return rather than "proposing" a change, and it does not say "Notice of Deficiency" or "you have 90 days"), the most important thing you can do is request abatement in writing within 60 days. That single step converts a take-it-or-leave-it correction back into a dispute you can actually take to court. Do not file Form 8862 in response to a math-error notice—that form is for reclaiming the credit on a later return, not for fixing this one.

Someone Else Claimed Your Child: The CP87A Notice

If you got a notice headed CP87A, take a breath—it is not an audit and it does not say you owe anything. CP87A is the IRS's duplicate-dependent notice: it means the IRS received another return claiming a dependent or qualifying child with the same Social Security number as one on your return. The notice shows only the last four digits of the SSN at issue.

Read what CP87A actually says, because it is gentler than it looks:

• "No, we're not auditing you at this time." It is informational. The IRS is not proposing tax and not holding your refund based on this notice alone.
• If you are entitled to the claim, you do not need to write back. You keep your records and wait. The IRS typically sends a matching CP87A to the other person who used that SSN, nudging whoever is wrong to fix it.
• If you realize you should not have claimed the child, you correct your return by filing a Form 1040-X amended return. (See How To File an Amended Return.)

This is the usual reason a second return gets rejected when you try to e-file: the IRS has already accepted a return with that child's SSN, so the system bounces yours. That rejection is not a ruling that you are wrong—it just means you have to file on paper and let the duplicate-claim process play out.

So who actually wins the child when two people both have a real claim? That is decided by the tie-breaker rules in § 152(c)(4)—a fixed order the IRS applies when more than one taxpayer can claim the same child:

1. A parent beats a non-parent. If one claimant is a parent and the other is a grandparent, aunt, or anyone else, the parent wins.
2. Between two parents who don't file jointly together, the child goes to the parent the child lived with for more nights during the year.
3. If the nights are equal, the parent with the higher adjusted gross income (AGI) wins.

What controls is where the child actually slept—the number of nights—not who pays support, not a custody decree's "right of first refusal," not whose "turn" it is this year. (The one big exception is a valid Form 8332 release between divorced or separated parents, covered next.) The EITC guide walks through this tie-breaker in more detail and from the EITC angle; if you want the full version, read it there.

"But the other parent already got the refund." Whoever filed or got paid first does not win. Entitlement is decided by where the child actually lived and the tie-breaker, and the IRS pursues the wrong claimant for the money back regardless of who was paid first.

A grandparent (or other relative) in the mix, or nights that feel 50/50. Residency is counted in actual overnights with each person, and a grandparent or other relative can win the child only if no parent qualifies. If you think your nights are 50/50, count the actual overnights for that specific year—a year has an odd number of nights, so there is almost always a winner, and the loser should concede rather than have both returns audited.

What this means for you in practical terms. If you are the parent the child lived with most of the year, and you have proof—school, medical, or childcare records showing the child's address—you are positioned to win the duplicate-claim fight when it escalates to an audit. Build that proof now. But if you are the one who is going to lose the tie-breaker—the parent with fewer nights, or a relative when a parent also claimed—digging in only adds penalties and interest. The cleaner move is to concede that child and amend your return for that year before the IRS forces the issue.

Divorced or Separated Parents: Form 8332

This is the heart of the most common contested Child Tax Credit case, and it is the one where confident people are most often wrong. The special rule for divorced and separated parents is IRC § 152(e).

Bottom line up front: yes, a noncustodial parent can claim the child's CTC—but only one way: the custodial parent must sign Form 8332 and you must attach it to your return for every year you claim. Nothing else works—not a divorce decree, not a verbal agreement, not paying all the support.

The default. When parents are divorced, separated, or live apart for the last six months of the year, the child is the qualifying child of the custodial parent—defined as the parent the child lived with for the greater number of nights during the year. A tie goes to the higher-AGI parent. The custodial parent owns the claim by default.

The release. The noncustodial parent can claim the child only if the custodial parent signs a written release and the noncustodial parent attaches it to their return for every year claimed. That release is Form 8332, "Release/Revocation of Release of Claim to Exemption for Child by Custodial Parent." Its three parts do three jobs:

• Part I releases the current year.
• Part II releases future years (you list the years, or write "all future years").
• Part III revokes a release you gave earlier.

"We agreed to alternate years." That only works if the custodial parent actually signs a Form 8332 for each year it's the other parent's turn (Part II can release several future years at once). Without the signed form for that specific year, the alternating deal is unenforceable against the IRS, and the custodial parent wins by default.

The rule that surprises almost everyone: a divorce decree cannot do the job of Form 8332. If the divorce or separation went into effect after 2008, the noncustodial parent cannot attach pages from the decree instead of the form. The form itself says so. Only an older decree (post-1984, pre-2009) can substitute, and only if it is unconditional—it states the claim without making it depend on anything, such as being current on child support—names the years, and includes the signature page. The number of parents who lose this fight because they relied on "the decree says I get to claim him" is large, and the law does not bend.

Revocation timing. A Part III revocation takes effect no earlier than the tax year after the custodial parent gives the noncustodial parent a copy (or makes a reasonable effort to). So a revocation handed over in 2025 is effective for 2026 at the earliest—you cannot yank back a release mid-year. Keep proof you delivered it.

The most important limit of Form 8332. It transfers only the dependency claim, the Child Tax Credit, the Additional Child Tax Credit, and the $500 ODC. It does not transfer the EITC, Head of Household filing status, or the child-and-dependent-care credit. Those always stay with the custodial parent—the parent the child actually lived with—and cannot be released by any form or decree. If you are the custodial parent and the IRS denied your EITC or Head of Household status because the other parent has a Form 8332, that is your winning argument: the form never reached those benefits. (If a joint return with a former spouse is what put you in trouble, that is a different remedy—see How To Request Innocent Spouse Relief.)

The Tax Court applies these rules strictly, and pro se parents have learned it the hard way. In Armstrong v. Commissioner, 139 T.C. 468 (2012), affirmed at 745 F.3d 890 (8th Cir. 2014), a father had a state-court order letting him claim his child—but the order was conditioned on his being current on support. He represented himself. The court held that a conditional order is not a valid release: § 152(e) requires an unconditional written declaration, and because the custodial parent never signed the actual Form 8332, both the dependency exemption and the child tax credit were disallowed. The father had paid his support in full. It did not matter—the form is the form.

The companion case is Shenk v. Commissioner, 140 T.C. 200 (2013). A divorced father whose children lived mostly with their mother claimed them without a signed Form 8332. The court held he was not entitled to the dependency exemption, not entitled to the child tax credit, and not entitled to Head of Household status—one missing form knocked out all three at once. A decree dividing up the children between the parents could not supply the release the law requires; residency controls, and the custodial parent had not signed off.

The lesson from both: if you are the noncustodial parent, a signed, unconditional Form 8332 attached to your return is not optional—it is the whole case. Without it, you lose, no matter how fair your decree feels.

Proving Your Claim: The Form 886-H-DEP Walk-Through

When a Child Tax Credit dispute turns into a real audit, the IRS tells you exactly what to send. The checklist is Form 886-H-DEP, "Supporting Documents for Dependents." Build your package to its sections, line by line—the IRS evaluates against this list, so answering it directly is how you win on paper.

Relationship. Only needed if the child is not your own natural or adopted child. Birth certificates that trace the relationship—for a grandchild, your child's birth certificate plus the grandchild's; for a niece or nephew, a chain of certificates sharing a common parent's name; for a step-relationship, certificates plus the marriage license. Adoption or foster-placement papers also work.

Residency (the hard one). To show the child lived with you for more than half the year, the IRS wants records that put your name, the child's name, your common address, and dates on the same page:

• School records
• Medical records
• Daycare or childcare provider records
• Social-service or court records
• A letter on official letterhead from a school, medical provider, social-service agency, or place of worship showing the names, the shared address, and the dates

The traps that sink residency proof, straight off the form:

• The records must be for the year in dispute. A school letter for this year does not prove where the child lived three years ago. Match the year exactly.
• "We cannot accept documents signed by someone related to you." If your mother or sister is the childcare provider, her letter will not work as residency proof. The signer must be an independent third party.
• Non-English documents need a certified translation.
• One good document can prove more than one thing—a single school record can cover residency and sometimes relationship at once.

"I have no documents." You can often request the records you need—school enrollment history, clinic or medical visit records, or a benefits-agency address history—and an LITC can help you assemble a residency package. A bare affidavit is weak, but third-party records you don't currently hold can usually be obtained.

For divorced or separated parents, Form 886-H-DEP also asks for the entire divorce decree or separation agreement, the current custody order, and a completed Form 8332 or similar statement. And here is a detail worth quoting because it settles the age argument straight from the IRS's own form: it notes that the under-19 age requirement is "for Earned Income Tax Credit eligibility only. For the Child Tax Credit, by the end of the year, the child must be under age 17." If anyone tells you a 17-year-old qualifies for the CTC, the IRS's form says otherwise.

For the residency-evidence deep dive—what each document needs to show, how to handle a P.O. box, how temporary absences count—the EITC and dependent-claims guide is the fuller reference, and everything it says about EITC residency proof applies to the Child Tax Credit too.

The Two-Year Ban and Form 8862

First, the reassurance: most denials carry no ban at all. An ordinary documentary loss—you simply couldn't prove residency in time—is not "reckless disregard" and usually carries no ban. The bans below are for a narrower, worse kind of conduct.

A Child Tax Credit denial can still cost you more than the credit for the year in dispute. IRC § 24(g) attaches a ban for future years in those harder cases:

• A two-year ban on claiming the CTC if the disallowance was "due to reckless or intentional disregard of rules and regulations (but not due to fraud)." Reckless disregard is a lower bar than fraud—claiming a child you knew did not live with you can be enough.
• A ten-year ban if the disallowance was "due to fraud."

This is why responding properly the first time matters. A casual "they denied it, I'll just claim it again next year" is exactly the conduct that produces a reckless-disregard finding and a two-year ban.

After any CTC disallowance—even an ordinary one with no ban—you generally cannot claim the credit again until you file Form 8862, "Information To Claim Certain Credits After Disallowance," with a later return. The same form covers the CTC, ACTC, ODC, EITC, and the American Opportunity education credit—so one form recertifies all of them.

Two times not to file Form 8862: (1) during a year you are still inside an active ban—you wait the ban out, you do not file the form; and (2) if the prior denial was only a math or clerical error, like the SSN math-error correction described above. Form 8862 is for reclaiming the credit on a future return, never for responding to the current notice.

The Burden Is on You, and How To Check the IRS's Numbers

In Tax Court, the IRS's determination is presumed correct, and you carry the burden of proving it wrong. The Supreme Court set that baseline a long time ago: in Welch v. Helvering, 290 U.S. 111 (1933), the Court treated the Commissioner's deficiency as presumptively right, leaving the taxpayer to overcome it. A "presumption of correctness" simply means the starting assumption is that the IRS got it right, and it is your job to show otherwise.

Credits make this even steeper. The Court held in New Colonial Ice Co. v. Helvering, 292 U.S. 435 (1934) that deductions and credits are a matter of "legislative grace"—they exist only because Congress granted them, so the person claiming one must show clear entitlement. The Child Tax Credit is grace, not a right. You have to prove you fit it.

IRC § 7491 can shift that burden to the IRS on a factual question, but it rarely helps here—it only kicks in if you first produce credible evidence and substantiated your claim and cooperated during the audit. The very thing that usually causes a CTC denial—not answering the audit letter, sending nothing—forfeits the shift. (One narrow tool: IRC § 6201(d) can put the burden of producing reasonable information on the IRS where the dispute hinges on an information return like a W-2 and you cooperated—relevant if the IRS is also questioning the earned income that drives your refundable ACTC.) Plan on the burden being yours, and win it with documents.

Before you concede a dollar, check the IRS's math—it can be wrong. Three steps:

• Read the actual notice and identify which one it is (the table below). The path forward depends entirely on whether you are holding a CP87A, an audit letter, a math-error notice, or a Notice of Deficiency.
• Get the examination report (Form 4549) if there is one. It lists every adjustment line by line—the disallowed CTC, the clawed-back ACTC, the recomputed tax, and any penalty. The IRS's recomputation can itself contain errors; do not assume the number is right.
• Pull your transcripts. Your Account transcript shows the assessments, codes, and dates; your Wage & Income transcript shows the income documents filed under your SSN, which confirms the earned income behind the $2,500 ACTC floor. Both are free and available to you directly through IRS.gov—you do not need a practitioner to get them. (Some transcripts, like the ones showing internal audit status, are practitioner-only, which is one good reason to bring in a free clinic.) See How To Get and Read Your IRS Transcripts and How To Read IRS Transcript Codes.

Here is how to tell the four notices apart:

The Full Exposure Picture: What This Actually Costs

Do not size the dispute by the credit alone. A Child Tax Credit denial after the refund was paid can stack into a bill several times larger than the credit, because the refundable piece is real cash and the penalties pile on top:

1. The disallowed nonrefundable CTC — up to $2,200 per child of tax benefit lost.
2. The refundable ACTC clawback — up to $1,700 per child of cash you already received that you now have to pay back.
3. The accuracy penalty (§ 6662) — 20% of the underpayment (not 20% of your income—people misread this constantly). See How To Fight the IRS Accuracy Penalty.
4. The erroneous-refund-claim penalty (§ 6676) — a possible additional 20% on the over-claimed refundable portion unless the over-claim was due to reasonable cause.
5. Interest — runs on the deficiency and penalties from the original due date of the return, compounded daily at the IRS underpayment rate (recently in the 7–8% range). See How Interest Works on Your IRS Tax Debt.
6. The future cost of the § 24(g) ban — two (or ten) years with no Child Tax Credit for the same family.

A worked example. Two qualifying children, 2025, the IRS denies both after the other parent also claimed them and you cannot prove residency in time:

• CTC/ACTC denied: about $4,400 in credits (2 × $2,200), of which up to $3,400 was refundable (2 × $1,700) and already paid out—so it has to be repaid.
• The deficiency lands around $4,400 (the nonrefundable CTC restored to tax plus the refundable clawback).
• The § 6662 accuracy penalty at 20% adds roughly $880.
• Interest over a 6-to-18-month case at about 8% adds a few hundred dollars more.
• And if the disallowance is found reckless, the two-year ban costs roughly $8,800 in lost CTC over the next two years (2 children × 2 years × ~$2,200).

So a "we both claimed the kids" mix-up becomes a $5,000-plus immediate bill with an $8,800 future tail. The flip side is the hopeful part: one clean, correct-year residency package—the documents on the Form 886-H-DEP list—can erase the immediate bill and head off the ban. The whole fight usually turns on whether you produce the right paper.

The amounts in these cases are almost always small in Tax Court terms, which matters for two reasons. A CTC deficiency is nearly always well under the $50,000 small-case threshold, so it can be handled as an informal "S case." And it is almost certainly under the $50,000 dispute limit for a free clinic—more on that below.

What To Do Now

Your move depends entirely on which letter you are holding. Match yours to the path:

If it is a CP87A (someone else claimed your child): you do not have to respond to the IRS unless you were the one who claimed wrongly. If you are entitled to the child, gather and keep your residency proof now—school, medical, or childcare records for that year—because the duplicate claim will likely escalate to an audit where you will need it. If you were not entitled, file a 1040-X to back out the claim.

If it is a math-error notice (a CP11 or CP12 that already changed your numbers, usually over a missing or wrong SSN): the clock is 60 days. Request abatement in writing within that window to force the IRS onto the deficiency track, where you keep your right to petition Tax Court before paying. Missing those 60 days does not end everything, but it pushes you into slower audit reconsideration or refund-claim channels.

If it is an audit letter (CP75 or Letter 566 holding your refund): respond by the date on the letter—usually about 30 days—with the Form 886-H-DEP package addressed line by line. Many of these never become a court case because clean proof ends them at the audit stage.

If it is a Notice of Deficiency (a Letter 3219 or CP3219A—the 90-day letter): you have 90 days from the date on the notice—150 days if you are addressed outside the US—to file a petition in US Tax Court. This deadline cannot be extended. Filing in time stops assessment and collection while your case is pending, and lets you fight without paying first. See How To File Your Tax Court Petition.

Once you are in Tax Court, a few things are true for nearly every CTC case:

• It is almost always a small case. Because the dollars are low, you can elect the simplified "S case" procedure—informal, plain-English, no rigid rules of evidence. The trade-off is that an S-case decision is final and sets no precedent, which most pro se petitioners accept gladly.
• The filing fee is $60, and a fee waiver is available if you cannot afford it—and given the income levels in these cases, most petitioners qualify.
• Most cases settle on the documents. Most (76%) of Tax Court cases close by settlement, and more than 99% are resolved without a trial on the merits. When you produce genuine residency and relationship proof, IRS Counsel frequently concedes and you get a stipulated decision (a settlement the judge signs off on) restoring the credit—no trial. See How To Settle Your Tax Court Case. These cases typically take 6-18 months to resolve.
• If the 90 days lapsed, audit reconsideration is the fallback—asking the IRS to reopen the assessment with the proof you never sent. It is discretionary, not a right, and does not stop collection on its own. But it works in many CTC cases precisely because the issue is purely documentary.

Get free help—you almost certainly qualify. This is one of the strongest fits for a Low-Income Taxpayer Clinic on the entire site. CTC eligibility and the income levels behind a refundable ACTC put nearly everyone in this situation under the clinic income ceiling (250% of the poverty line), the dispute is under the $50,000 limit, and clinics handle exactly these audits and Tax Court small cases every day—for free or a nominal fee. Reach one the day you get the letter, not after a Notice of Deficiency. See How To Find and Use a Low-Income Taxpayer Clinic. If your case also involves a CP2000 notice on other income, that runs as a related but separate process.

Resources

• IRC § 24 — Child tax credit
• IRC § 152 — Dependent defined
• IRC § 6213 — Petition to Tax Court; math-error and 90-day rules
• IRC § 7491 — Burden of proof
• IRC § 6662 — Accuracy-related penalty
• IRC § 6676 — Erroneous claim for refund or credit
• About Schedule 8812 (Form 1040) — figuring the CTC, ACTC, and ODC
• 2025 Instructions for Schedule 8812
• Form 8332 — Release/Revocation of Claim to Exemption for Child
• Form 886-H-DEP — Supporting Documents for Dependents
• Form 8862 — Information To Claim Certain Credits After Disallowance
• IRS — Child Tax Credit
• Understanding Your CP87A Notice (IRS)
• Publication 501 — Dependents, Standard Deduction, and Filing Information
• Starting a Case (US Tax Court)

Cases cited:

• Armstrong v. Commissioner, 139 T.C. 468 (2012), aff'd, 745 F.3d 890 (8th Cir. 2014)
• Shenk v. Commissioner, 140 T.C. 200 (2013)
• Welch v. Helvering, 290 U.S. 111 (1933)
• New Colonial Ice Co. v. Helvering, 292 U.S. 435 (1934)

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