The Tax Side of a Late-Life Divorce
A separation after decades of marriage divides assets that carry different tax characters, changes both people's filing status, and produces support payments whose treatment changed fundamentally a few years ago. None of it is complicated individually, and all of it decides whether a settlement that looks equal actually is.
- The 2019 change:: Under agreements executed after 2018, alimony is not deductible and not taxable.
- Older agreements continue:: Pre-2019 agreements keep the old treatment unless modified to adopt the new rules expressly.
- Property transfers carry basis:: Assets divided incident to divorce transfer at basis rather than at market value.
- Filing status changes on 31 December:: Marital status on the last day of the year determines the whole year's filing status.
Where the AI summary above gets this wrong
"Alimony is deductible by the payer and taxable to the recipient."
That's surface-true. Here's what it misses:
- That reversed for agreements made from 2019 — Payments under agreements executed after 2018 are neither deductible nor taxable. The arrangement that used to move income from a higher-rate payer to a lower-rate recipient — generating a saving that helped fund the settlement — no longer exists, and settlements negotiated on the old assumption are simply more expensive.
- An equal split of assets is rarely an equal split after tax — A $500,000 traditional IRA and a $500,000 taxable account are not equivalent. The IRA carries deferred income tax on the whole balance; the taxable account carries capital gains tax on the appreciation only, and receives a step-up at death. Dividing by market value alone hands one person a larger liability.
- The retirement accounts need their own order — An employer plan is divided by a qualified domestic relations order, and an IRA by instruction to the custodian under the decree. Getting the mechanism wrong turns a transfer into a taxable distribution, which is the rollover trap in a different setting.
01 The alimony change
For agreements executed after 2018, payments are neither deductible by the payer nor included in the recipient's income. Agreements executed before that keep the old treatment — deductible and taxable — unless they are modified and the modification expressly adopts the new rules.
The old treatment produced a genuine saving between the two households whenever the payer's rate exceeded the recipient's. That saving was frequently what made a support figure affordable, and its removal means a given payment now costs the payer considerably more in after-tax terms.
Child support has never been deductible or taxable, and payments that are in substance child support are treated as such regardless of labelling. State treatment does not always follow the federal rule, which is a further check to make.
Shows: the tax the two households saved between them under agreements made before 2019, where the payer deducted and the recipient was taxed. For newer agreements that saving no longer exists. Ignores: state treatment, which does not always follow the federal rule, and the effect of the payment on other income-tested items.
02 Dividing the assets
Property transferred between spouses incident to divorce is generally not a taxable event. The recipient takes the transferor's basis, which means the embedded tax travels with the asset rather than being settled at the point of division.
That is why market value is the wrong measure for an equal split. A pre-tax retirement account, a taxable portfolio with large unrealised gains, a Roth account and the family home all carry different effective values after tax, and only the Roth is worth its face amount.
The home has its own rules. The exclusion on a sale depends on ownership and use tests that a divorce can disrupt, and a settlement where one spouse remains in the house for years before selling needs the housing decision and the exclusion checked together.
Source: Publication 504
03 Filing status and the year of separation
Marital status on 31 December determines filing status for the whole year. A divorce final on 30 December means filing as single or head of household for that entire year; one final on 2 January means a final joint or separate married return.
That single date can be worth a great deal, and it is frequently within the parties' control. Where one spouse's income is much higher, the difference between a joint return and two single ones is a real number worth putting in front of both lawyers.
Two further items belong on the list. Update every beneficiary designation, since the will does not control retirement accounts or life insurance. And check the Social Security position, because a marriage of at least ten years produces a claim on the former spouse's record that survives the divorce entirely.
Source: Publication 501
The single most useful thing to bring to a late-life divorce is a schedule of assets with their after-tax value, not their statement value. A pre-tax IRA, a Roth and a brokerage account of the same size are three different amounts of money, and dividing them as though they were equal quietly hands one person a worse outcome. That schedule takes an afternoon and it changes what a fair settlement looks like.
FAQ
Is alimony still deductible?
Not under agreements executed after 2018 — those payments are neither deductible nor taxable. Earlier agreements keep the old treatment unless modified to adopt the new rules expressly.
Is an equal split of assets really equal?
Rarely, before tax is considered. A pre-tax retirement account carries deferred income tax on the whole balance, while a taxable account carries capital gains tax on the appreciation only and a Roth carries none.
What filing status applies in the year of divorce?
Marital status on 31 December determines the whole year. A divorce final in December means filing as single or head of household for that entire year.
Sources
Regulator references
- Topic 452: alimony and separate maintenance · Internal Revenue Service · 2026The treatment of payments under agreements before and after the 2018 change.Last verified: 2026-09-07
- Publication 504 · Internal Revenue Service · 2026Filing status, property transfers and dependants after a separation.Last verified: 2026-09-07
- Publication 501 · Internal Revenue Service · 2026Which filing status applies and when the change takes effect.Last verified: 2026-09-07
Calculator unit tests · the assertions this page's worked example is checked against, and their last result
Changelog
- 2026-09-07 — initial publish (new format)
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Jordan Reeves
Founder of Talk Through Wealth. A software engineer for over a decade before turning to retirement planning, Jordan built the projection engine after watching family members get fragmented, country-by-country advice that never reconciled. He writes about retirement the way the engine computes it: month-by-month, lifetime-long, and skeptical of any rule of thumb that hasn't been run through the math.