What can take a joint refund, and in what order. Section 6402(a) lets the IRS apply an overpayment "against any liability in respect of an internal revenue tax on the part of the person who made the overpayment", and then refund the balance "subject to subsections (c), (d), (e), and (f)". Those four are the non-tax offsets, and each carries its own priority sentence, so the sequence is fixed by statute rather than by practice:
- Federal internal revenue tax, under 6402(a).
- Past-due child support, under 6402(c), which directs that a reduction be applied "first to an amount certified by the State as past due support ... before any other reductions allowed by law". Since Public Law 118-258 the subsection expressly reaches an Indian tribe or tribal organization receiving a grant under section 455(f) of the Social Security Act as well as a State.
- Debts owed to federal agencies, under 6402(d), which places itself after support and before the state offsets, and applies competing federal debts "in the order in which such debts accrued".
- Past-due state income tax under 6402(e) and covered state unemployment compensation debts under 6402(f), each of which places itself after the internal-revenue, support and federal-agency reductions.
- Only then is anything credited forward to next year's estimated tax under 6402(b), which is why electing to apply a refund forward does not protect it.
Form 8379 lists the same categories in plainer words as "Federal tax, State income tax, State unemployment compensation, Child support, Spousal support, Federal nontax debt (such as a student loan)".
The offsets are not run by the IRS, and that changes who to call. The IRS states that "Debt offsets are conducted by the Department of Treasury's Bureau of the Fiscal Service (BFS)", which "issues IRS refunds and is authorized by Congress to conduct the Treasury Offset Program (TOP)". The letter that arrives is a Notice of Offset naming the original refund, the amount taken, the agency that received it, and that agency's contact details. Questions about the debt go to that agency; the IRS notes that "The details of the offset aren't provided to the IRS."
The form cannot challenge the debt or the offset, and the bar is statutory. Section 6402(g), headed "Review of reductions", provides that "No court of the United States shall have jurisdiction to hear any action, whether legal or equitable, brought to restrain or review a reduction authorized by subsection (c), (d), (e), or (f). No such reduction shall be subject to review by the Secretary in an administrative proceeding." The same subsection preserves action against the agency that received the money. So there are two separate arguments and they go to two different places: "this debt is not mine or not that much" goes to the creditor agency, and "some of that refund was mine" goes to the IRS on Form 8379.
Who actually qualifies, and the screen most people miss. Form 8379's Part I is a gate. A joint return must have been filed; the overpayment must have gone to a past-due debt "owed only by your spouse"; and the requesting spouse must not be legally obligated to pay it. Then comes the part that surprises people: outside a community property state, the form asks whether the requesting spouse made and reported payments such as withholding or estimated tax, or had earned income and claimed the earned income credit or additional child tax credit, or claimed some other refundable credit. If none of those is true there is nothing to allocate, and the instructions say plainly to stop and not file. A spouse with no income, no withholding and no refundable credit has no share of the overpayment to recover, however unfair the outcome feels.
Community property states change the arithmetic rather than the eligibility. Where the requesting spouse was a resident of a community property state at any time in the year, Form 8379 skips the income and payment questions entirely, and the IRS states that "If you lived in a community property state, we divide the refund based on state community property law." Because community property law generally treats income earned during the marriage as belonging equally to both spouses, the split can be very different from the who-earned-it answer, and it varies between the nine community property states. The IRS also notes that "Married persons who file separate returns in community property states may also qualify for relief."
Timing, and the two ways to file. The claim can go in with the joint return, by mail or electronically, or separately once a Notice of Offset arrives. Filing it with the return delays processing; the IRS says Form 8379 alone can take "up to 8 weeks to process ... and longer if you file it with your tax return." The deadline is the ordinary refund-claim window under section 6511: within three years of filing the return or two years of paying the tax, whichever is later, and where no return was filed, two years from payment. And it is per year: "You must file a new Form 8379 for each year when you want to reclaim a refund."
Filing separately is the alternative, and sometimes the worse one. A separate return carries no joint liability and no joint refund, so nothing can be taken for the other spouse's debt in the first place. But married filing separately strips out or halves a long list of credits and deductions, which is why an injured spouse allocation on a joint return is usually the cheaper way to protect a share of a refund.