RMD exceptions and fine print: still-working, aggregation, Roth 401(k)

Last reviewed July 2026 · 5 min read

The headline RMD rule is simple: reach your start age — 73 if you were born 1951–1959, 75 if 1960 or later^[2] — and pre-tax retirement money must start coming out, taxed as ordinary income. The fine print is where plans go wrong. Which accounts can be pooled, which must each pay their own way, who gets to delay, and which Roth money escapes entirely — the details differ by account type, and mixing them up carries a real excise tax.

The still-working exception

If you are still employed past your RMD start age, your current employer’s plan — a 401(k), 403(b), or similar — can let you delay RMDs from that plan until April 1 of the year after you retire^[1]. Three catches. It never applies to IRAs, SEPs, or SIMPLE IRAs: those start on schedule no matter how hard you are working^[2]. It never applies if you own more than 5% of the business sponsoring the plan^[1]. And it is a plan feature, not a legal right — the plan document may require distributions at 73 regardless, so check before counting on it^[5]. Old 401(k)s at former employers get no such grace; one common move is rolling them into the current employer’s plan (if it accepts roll-ins) so the exception covers those dollars too.

Aggregation: which accounts can share one withdrawal

RMDs are always calculated account by account, but where the money actually comes from depends on the account type. Under 26 CFR §1.408-8, an IRA owner sums the separately calculated RMDs for all their IRAs and may take the total from any one or combination of them^[4] — handy for draining a small IRA or leaving an illiquid one untouched. 403(b) contracts work the same way among themselves. 401(k)s do not: each 401(k) must distribute its own RMD, separately^[1]. And the categories never cross — an IRA withdrawal cannot satisfy a 401(k) RMD, spouses cannot take each other’s, and inherited IRAs aggregate only with other IRAs inherited from the same person. The 2026 shape of the rules, in brief: IRAs pool, 403(b)s pool, 401(k)s stand alone.

Roth accounts: mostly exempt now

Roth IRAs have never had lifetime RMDs^[3]. Designated Roth accounts inside a 401(k) or 403(b) used to — an odd asymmetry that pushed retirees to roll Roth 401(k) money to a Roth IRA just before their start age. SECURE 2.0 ended that: starting in 2024, designated Roth accounts have no lifetime RMDs either^[2]. Two footnotes survive. Beneficiaries who inherit Roth money are subject to post-death distribution rules (for most non-spouse heirs, the 10-year rule). And your Roth balances still don’t help your pre-tax RMD — the calculation runs on traditional dollars only.

The first-year trap and the penalty

Your very first RMD may be delayed until April 1 of the following year (the “required beginning date”)^[1]. Convenient — until you notice the second RMD is still due by December 31 of that same year^[1], stacking two taxable RMDs into one tax year, possibly right into a higher bracket or across an IRMAA threshold. Missing an RMD entirely triggers an excise tax of 25% of the shortfall, reduced to 10% if you correct it within the two-year correction window (both down from the old 50%), reported on Form 5329 with a request for waiver available for reasonable errors^[2].

What this means for planning

The exceptions are timing tools, not escapes. Still-working delays shift RMDs later — into fewer, larger years. Aggregation changes which account writes the check, not the tax bill. The durable moves are the ones that shrink the pre-tax balance before the conveyor starts: Roth conversions in low-income years, and qualified charitable distributions from 70½ for money you would give away anyway.

Try it in Deorbit Plan

Deorbit Plan models each person’s pre-tax money as a single pooled balance — effectively the IRA aggregation view — with RMDs starting at your SECURE 2.0 age (the still-working exception is not modeled). The RMDs vs spending chart shows when forced withdrawals overtake what you actually need. To shrink them, open the Strategy panel: set a Roth conversion strategy (fixed amount or fill-to-bracket) for the years before your start age, and use Qualified charitable distributions from age 70½ ($/yr) to route giving straight from the IRA. Roth balances in the Accounts panel are never RMD’d, matching the post-2024 rules. Compare scenarios A/B to see how much each lever flattens the late-life tax spike.

Educational content only — not financial, tax, or investment advice.

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