Whose Income Is It, Anyway?

The nine states — domicile decides, not the return

Nine states run on community property law: Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, and Wisconsin. If you are married and DOMICILED in one of them — domicile is where your true home is, the place you intend to return to, not a mailing address or a winter stay — state law, not the name on the paycheck, decides whose income is whose for your federal return. Property and income acquired during the marriage while domiciled there are generally community: owned in undivided halves. What you owned before the marriage, and gifts and inheritances received alone, are generally separate. (A few other states let couples ELECT community property treatment by agreement or trust — Publication 555 does not cover those elective regimes, and neither does this desk.) 🔊 Listen

Authority: Publication 555 (Rev. Dec. 2024), Introduction and “Domicile”

Filing jointly, nothing changes visibly — filing separately, everything does

On a joint return the community rules are nearly invisible: all the income lands on one return either way. They bite when a married couple in a community property state files SEPARATELY. Then each spouse reports exactly HALF of all community income — wages, salary, self-employment, most everything earned during the marriage — plus ALL of their own separate income, no matter whose name the W-2 carries. The spouse who earned $90,000 and the spouse who earned $10,000 each report $50,000 of the combined wages. And the state split has a second layer: in Arizona, California, Nevada, New Mexico, and Washington, income FROM separate property stays separate — but in Idaho, Louisiana, Texas, and Wisconsin, income from most separate property is itself community income, split down the middle too. The same couple, the same assets, a different state line, a different answer. 🔊 Listen

Authority: Publication 555, “Community or Separate Property and Income,” Table 1

Form 8958 — the allocation statement that must reconcile

Each spouse filing separately in a community property state attaches Form 8958, Allocation of Tax Amounts Between Certain Individuals in Community Property States: a line-by-line statement of the total amounts (both spouses combined), the amount allocated to each, by employer and by item — wages, interest, deductions, withholding, estimated payments. The two spouses' forms must mirror each other, and the IRS matches them; a 8958 that shows only your half, or percentages that don't reconcile to the W-2 totals, is an invitation to correspondence. Withholding splits the same way the income does — each spouse is credited with half the community withholding, whatever either paycheck actually withheld. Couples who file separately in these states without the 8958 have not filed the return the IRS expects. 🔊 Listen

Form: Form 8958, attached to each separate return (see the Forms Library)

Authority: Form 8958 and instructions; Publication 555, “Preparing a Federal Income Tax Return”

Registered domestic partners — California, Nevada, Washington

Registered domestic partners are not married for federal tax purposes — an RDP files federal taxes as single, or head of household if they qualify. But in the three states where Publication 555 applies community property law to RDPs — California, Nevada, and Washington — RDPs must generally follow their state's community property rules when reporting income federally: each partner reports half the combined community income, with Form 8958 doing the allocation. It is the one place the federal system applies the 50/50 machinery to people it does not count as spouses, and it produces the classic RDP puzzle: two single returns whose incomes are halves of one household's earnings. 🔊 Listen

Authority: Publication 555, “Registered Domestic Partnerships”

Relief path one — lived apart all year (§66(a))

Publication 555's “Community Property Laws Disregarded” section opens with the cleanest exit: married individuals who live apart for the ENTIRE calendar year, do not file a joint return, and during the year do not transfer (directly or indirectly) earned income between them that is community income — for those spouses, earned income is taxed to the spouse who earned it, and income from separate property follows that spouse, instead of being split. Miss any element — one month under one roof, one transfer of earned income — and the exception closes for the whole year. 🔊 Listen

Authority: IRC §66(a); Publication 555, “Community Property Laws Disregarded”

Relief path two — the spouse who acted as if it were theirs alone (§66(b))

Where one spouse treats an item of community income as belonging solely to themselves and does not notify the other spouse of its amount or nature before the return's due date (with extensions), the IRS may decide that item is taxed as the separate income of the spouse who actually received and controlled it — disregarding the 50/50 rule for that item. It is the remedy aimed at the kept-in-the-dark spouse: you cannot be split into income you were never told existed, if the IRS exercises this discretion on your facts. 🔊 Listen

Authority: IRC §66(b); Publication 555, “Community Property Laws Disregarded”

Relief path three — §66(c) equitable relief, and its innocent-spouse cousin

If you filed separately without including an item of community income, did not know (and had no reason to know) about it, and including it would be inequitable on all the facts, the IRS may relieve you of tax on that item under §66(c) — requested on Form 8857. Keep the families straight, because the forms blur: §66 relief defends the SEPARATE filer against the community split; classic innocent-spouse relief (also Form 8857, taught in Publication 971) defends a JOINT filer against the other spouse's errors on a return they both signed. One form, two different doors — a credentialed pro picks the door before anything is filed, because the wrong door wastes the request. 🔊 Listen

Form: Form 8857, Request for Innocent Spouse Relief (see the Forms Library)

Authority: IRC §66(c); Publication 555; Publication 971

The forfeit list — what the MFS box usually costs

Married filing separately is sometimes the right answer — it caps each spouse's liability at their own return, and it can lower payments where a benefit is keyed to one spouse's AGI. But price the whole list first. An MFS filer generally CANNOT claim: the Earned Income Tax Credit (a narrow lived-apart-with-qualifying-child exception exists); the American Opportunity and Lifetime Learning education credits; the student-loan interest deduction; or the premium tax credit for Marketplace coverage (with exceptions for domestic-abuse and abandoned spouses). The child and dependent care credit is generally closed too, unless the lived-apart rules are met. Amounts shrink across the board: the capital-loss allowance halves to $1,500, the rental real-estate loss allowance halves, and Social Security benefits hit the 85% tier from the first dollar for spouses who lived together. The Roth IRA door nearly closes — for an MFS filer who lived with their spouse at any time during the year, the contribution phase-out runs from $0 to $10,000 of income. 🔊 Listen

Authority: IRC §32(d); §25A(g)(6); §221(e)(2); §36B(c)(1)(C); §21(e)(2); §1211(b) (capital-loss limit); §469(i) (rental loss allowance); §86 (Social Security tiers); §408A(c)(2)(B) (Roth phase-out)

The SALT half-cap, already in the tables

The new SALT cap is halved for separate filers at every step: where joint and single filers get a $40,000 cap for 2025 ($40,400 for 2026) over a $500,000 phase-down threshold ($505,000 for 2026), a married-filing-separately return gets a $20,000 cap ($20,200 for 2026), a $250,000 threshold ($252,500), and the same $10,000 floor becomes $5,000. Two spouses filing separately in a high-tax state can therefore deduct, together, exactly what one joint return deducts — but each return must itemize on its own numbers to claim its half. The platform's tables carry the full derivation in the SALT card on Money Nobody Knew; the Studio's scope box names the cap rather than applying it silently. 🔊 Listen

Authority: IRC §164(b)(7) (MFS amounts are half); platform tax-year tables (SALT_CAPS)

When separate is still right — the short honest list

Three situations justify MFS despite the forfeits. Liability separation: a joint return makes each spouse liable for the whole tax — a spouse who does not want to underwrite the other's reporting files separately (and in a community property state, pairs it with the §66 analysis above, because separate filing alone does not fully separate community income). Income-driven student-loan payments: where a repayment plan keys the payment to the borrower's own AGI and state law permits excluding the spouse's income by filing separately — run BOTH returns both ways, because the MFS tax cost is paid in cash to save a loan payment. And medical or other AGI-floored deductions concentrated in the lower-earning spouse. The desk's rule: MFS is a computation, never a mood — price joint, price separate, price the community allocation, then choose with the numbers in front of you. 🔊 Listen

Authority: Publication 555 (“your tax will usually be less if you file jointly” — verify both ways); Publication 501, filing-status guidance