Oklahoma guide
The backdoor Roth, the mega-backdoor Roth,
and which Oklahoma City plans allow them.
High earners in Oklahoma City are told constantly to “do the backdoor Roth” and far less often what it is, whether their own plan permits the bigger version, or what the pro-rata rule does to it. This page answers all three. The employer table is built from the plans’ own filings, and where a plan’s documents are not public we say so rather than guess.
What is the backdoor Roth, and what is the mega-backdoor Roth?
A backdoor Roth is a nondeductible contribution to a traditional IRA (up to $7,500 in 2026, plus $1,100 at 50 or older) followed by a conversion of that IRA to a Roth IRA, which works regardless of income because conversions have no income limit. A mega-backdoor Roth is the same idea inside a 401(k): after-tax contributions above the $24,500 deferral limit, up to the $72,000 overall limit for 2026, moved to Roth through an in-plan conversion or a rollover to a Roth IRA. The first is available to anyone with earned income; the second only if the employer’s plan allows after-tax contributions and a way out.
Source: IRS Notice 2025-67, 2026 limits · 26 U.S.C. § 402A(c)(4) · IRS Notice 2014-54
Reviewed by Jeremy Baldwin, Founder & Private Wealth Advisor, Baldwin Financial, Oklahoma City. Last reviewed October 2026.
The rule
Five facts, each with its source.
Everything below comes from the Internal Revenue Code, the IRS notices that set the limits and the mechanics, and the plans’ own filings. If a number here ever disagrees with one of them, the source wins and we fix the page.
The 2026 limits: $24,500 of deferrals, $72,000 all in, $7,500 for an IRA.
Your own pre-tax and Roth 401(k) contributions are capped at $24,500 for 2026. Everything that goes into your account from all sources, your deferrals, the employer’s match and contributions, and any after-tax contributions, is capped at $72,000. Catch-up contributions sit outside both: $8,000 at 50 or older and $11,250 at ages 60 through 63. IRAs are $7,500, plus $1,100 at 50 or older.
The Roth IRA income limit is real; the conversion income limit is gone.
Direct Roth IRA contributions phase out between $153,000 and $168,000 of modified adjusted gross income for single filers in 2026, and between $242,000 and $252,000 for joint filers. There has been no income limit on converting a traditional IRA to a Roth since 2010. Put the two together and the backdoor appears. The 2017 Conference Report on the Tax Cuts and Jobs Act describes exactly this sequence in a footnote, which is as close as Congress comes to a blessing.
The pro-rata rule is what makes the backdoor clean or messy.
When you convert, the IRS treats all of your traditional, SEP and SIMPLE IRAs as one pot, and the converted amount is taxable in the same proportion as the pot is pre-tax, measured on December 31 of that year, on Form 8606. If you have $7,500 of new nondeductible money and $142,500 in an old rollover IRA, 95% of the conversion is taxable. The usual fix is rolling the pre-tax IRA money into your 401(k) first, which most large plans accept; confirm that yours does.
The mega version needs two things from your plan: after-tax contributions, and a way out.
After-tax contributions are a separate bucket from Roth deferrals and most plans do not offer them. The ones that do then need either an in-plan Roth conversion under § 402A(c)(4), or an in-service withdrawal of the after-tax account that you roll to a Roth IRA, which IRS Notice 2014-54 lets you do while sending any earnings to a traditional IRA. The sooner the money moves, the less of it is earnings, which is why some plans convert automatically every payday.
Oklahoma taxes a conversion the same year the IRS does, at 4.5%.
Oklahoma starts from federal adjusted gross income, and its Form 511 instructions say rollovers and IRA conversions are taxed in the same year as on the federal return. There is no Oklahoma add-back or penalty. Oklahoma’s $10,000 retirement-income exclusion is written for benefits received, and the Tax Commission has not said whether a conversion counts; ask your preparer rather than assume.
The employers
Who allows what, from the plans’ own documents.
This table is built from Form 11-K annual reports filed with the SEC, plan documents, and official plan summaries, each dated. Features change, so treat it as the right question to ask HR, with the answer we could verify. Employers whose plan features we could not verify from a public filing (Paycom, Love’s, Hobby Lobby, Expand Energy, INTEGRIS, OU Health, Mercy and SSM Health among them) are not listed, not because the answer is no, but because we could not confirm it, and we would rather you ask than trust a guess.
| Employer | Plan | After-tax contributions | Roth 401(k) | Path to Roth, and notes | Verified from |
|---|---|---|---|---|---|
| Boeing (Oklahoma City) | The Boeing Company 401(k) Retirement Plan, Fidelity | Yes | Yes | After-tax money can be withdrawn at any time and rolled to a Roth IRA; in-plan conversion is not described in the plan’s 2025 annual report, so confirm on NetBenefits | Form 11-K, June 2026 |
| OGE Energy / OG&E | Employees’ Stock Ownership and Retirement Savings Plan | Yes | Yes | In-service withdrawal of after-tax money is allowed; the plan’s in-plan Roth rollover is written for pre-tax money only. Match is 200% of the first 5% for hires since December 2009 | Form 11-K, June 2026 |
| ONE Gas | ONE Gas, Inc. 401(k) Plan | Yes, up to 6% of pay | Yes | After-tax money can be withdrawn in service ($500 minimum), so the Roth IRA route works; the 6% cap keeps it modest | Form 11-K, June 2026 |
| Devon Energy | Devon Energy Corporation Incentive Savings Plan | No | Yes | No after-tax contributions in the 2022 plan document. Pre-tax balances can be converted to Roth inside the plan. Devon also contributes 8% of pay plus a match, which uses up most of the $72,000 limit anyway | Plan document, 2022 restatement |
| Continental Resources | 401(k) administered by Fidelity | Not stated | Yes | Match of $1 for $1 up to 10%, vested after two years. The benefits guide does not mention after-tax contributions; ask for the summary plan description | 2026 and 2027 benefits guides |
| Tinker AFB, federal civilians and military | Thrift Savings Plan | No | Yes | The TSP has no after-tax (non-Roth) option, so there is no mega-backdoor. Since January 28, 2026 it allows Roth in-plan conversions of pre-tax money, with the tax paid from outside funds | tsp.gov, January 2026 |
| State of Oklahoma employees | SoonerSave 457(b) and 401(a) | No | Yes | Roth 457 contributions are allowed. A governmental 457(b) has no after-tax option and its own separate $24,500 limit, which stacks with a 403(b) or 401(k) limit | SoonerSave plan highlights, 2026 |
| University of Oklahoma and OSU | Voluntary 403(b) and 457(b), Fidelity (OU) and TIAA (OSU) | Not stated | Yes | Roth 403(b) and Roth 457(b) are both offered, and the two limits stack to $49,000 before catch-ups. After-tax contributions are not mentioned | OU and OSU HR, 2026 |
What to ask HR, in one sentence: does the plan allow after-tax (non-Roth) employee contributions, up to what percentage, and can the after-tax account be converted to Roth inside the plan or withdrawn in service and rolled to a Roth IRA? Then ask whether the plan accepts roll-ins of pre-tax IRA money, which is how you clear the pro-rata problem before a backdoor contribution.
The trap
Three ways this goes wrong, all avoidable.
None of these is exotic. They are the ordinary mistakes we see, and each one is a sentence of foresight.
A rollover IRA from an old job makes the backdoor mostly taxable.
The pro-rata rule counts every traditional, SEP and SIMPLE IRA you own on December 31, not just the one you converted from. The $200,000 rollover from a previous employer, sitting quietly at another custodian, turns a $7,500 backdoor into a largely taxable conversion. Roll it into your current 401(k) before year-end, or do the backdoor in a year when the IRA balance is zero on December 31.
Money that sits in the after-tax bucket grows pre-tax, and the growth is taxable when converted.
After-tax contributions are tax-free to convert; the earnings on them are not. A plan that lets you convert daily or each pay period keeps the taxable slice near zero. One that only allows an annual in-service withdrawal can leave a year of market growth to be taxed, or sent to a traditional IRA under Notice 2014-54, which then reintroduces the pro-rata problem. Know the cadence before you start.
From 2026, catch-up contributions must be Roth if you earned more than $150,000 last year.
Under SECURE 2.0, anyone whose prior-year FICA wages from the employer exceeded $150,000 (the 2025 figure, indexed) must make catch-up contributions as Roth. If the plan has no Roth feature, those employees cannot make catch-ups at all. That is $8,000 a year, or $11,250 at ages 60 to 63, that disappears from a plan that never added the Roth option. It is also a reason to check that your plan’s Roth feature is switched on, not just permitted.
The decision
Who should bother, and in what order.
Roth dollars are most valuable to people who will be in a similar or higher bracket later, who have decades for the account to compound, or who want a pool of money that never carries a required minimum distribution and passes to children free of income tax. That describes a good share of Oklahoma City’s physicians, executives and engineers at the companies in the table. It describes almost nobody in a brief high-income year who will retire into a much lower bracket; for them, pre-tax contributions and a conversion in a cheap year do the same job for less.
The order we use: capture the full employer match; then max the $24,500 deferral, choosing Roth or pre-tax based on today’s bracket against your likely one in retirement; then the $7,500 Roth IRA, through the back door if your income requires it and your IRA balance allows it; then after-tax contributions up to the $72,000 limit if the plan permits them and converts them promptly. A household that completes all four can put more than $60,000 a year into Roth accounts with no income test anywhere in the chain.
Where Oklahoma adds a twist: the state’s 4.5% rate makes a conversion a little cheaper here than in many states and a little more expensive than in Texas, and the rate could fall a quarter point at a time from 2027 if the state’s revenue triggers are met. A conversion planned for a year after a trigger has fired is worth a quarter point more than one done today, which is not nothing on a six-figure conversion.
Run your numbers
How much Roth can you add this year?
Enter how you file, your modified adjusted gross income, what you are already putting into your 401(k), and what your employer contributes. The calculator applies the 2026 Roth IRA phase-outs and the $72,000 overall plan limit. Nothing you enter leaves your browser.
- Direct Roth IRA contribution allowed
- Backdoor Roth IRA, if needed
- Room left under the $72,000 plan limit
- Total Roth dollars possible this year
Questions we get
Asked often enough to answer here.
Is the backdoor Roth legal?
Yes. There is no income limit on converting a traditional IRA to a Roth IRA, and nondeductible IRA contributions are allowed at any income. The 2017 Conference Report on the Tax Cuts and Jobs Act describes the contribute-then-convert sequence directly. The one rule that bites is the pro-rata rule, which taxes the conversion in proportion to any pre-tax IRA money you hold on December 31.
What is the difference between a Roth 401(k) contribution and an after-tax contribution?
A Roth 401(k) contribution is part of your $24,500 deferral limit and its earnings are tax-free. An after-tax contribution is a separate bucket above the deferral limit, up to the $72,000 overall limit, whose earnings are taxable until the money is converted to Roth. The mega-backdoor Roth is the act of converting that after-tax bucket.
Which Oklahoma City employers allow the mega-backdoor Roth?
From the plans’ own filings: Boeing, OGE Energy and ONE Gas allow after-tax contributions with a way to move them to Roth (ONE Gas caps after-tax at 6% of pay). Devon does not allow after-tax contributions. The federal Thrift Savings Plan and the state’s SoonerSave plan have no after-tax option. For employers whose plan documents are not public, ask HR for the summary plan description.
Does Oklahoma tax a Roth conversion?
Yes, as ordinary income in the same year as the federal return, at Oklahoma’s rate of 4.5% for 2026. There is no Oklahoma penalty or add-back. Whether a conversion qualifies for Oklahoma’s $10,000 retirement-income exclusion is not addressed by the Tax Commission; ask your preparer.
Does Baldwin Financial manage 401(k) accounts?
We advise on them as part of a financial plan: which contribution type to use, how to allocate the plan’s menu, and when to convert. The plan itself stays with your employer’s provider. Baldwin Financial is a fee-only fiduciary adviser and receives nothing from any plan or provider named on this page.
An invitation
The limits are public.
Which bucket to fill first is the plan.
A complimentary conversation, by video, phone, or in person in downtown Oklahoma City, at a time that works for you. Nothing to prepare and nothing to bring. Come as you are; leave knowing more than you arrived with.
What the conversation looks like
- 01
You talk. What you own, what you owe, who depends on you, and whatever is coming up that you have not solved yet.
- 02
We tell you what we see. The two or three things we would look at first, and why those and not the rest.
- 03
You decide, on your own time. If we are not the right fit, we will say so and point you toward someone who is.
Or reach us directly
- Phone
- (405) 266-7856
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- 629 W. Main Street, Suite 10080, Oklahoma City, OK 73102
In person downtown, or by video - Serving
- Oklahoma City, Edmond, Nichols Hills, and clients who have moved away
This guide is educational and general. It describes federal and Oklahoma rules as published on the date shown in the footer, which can change, and it is not personalized tax, legal or investment advice. The employer table summarizes publicly filed plan documents on their stated dates; plan features change and your plan’s summary plan description governs. Baldwin Financial, LLC is not affiliated with any employer, plan or provider named here and receives no compensation from any of them. The calculator is an illustration using 2026 limits and does not account for catch-up contributions, multiple employers, or the pro-rata rule.