The Mega Backdoor Roth: How Central New Jersey Executives and Business Owners Can Move Far More Into Tax-Free Growth in 2026

For people whose 401(k) plan allows it, this strategy can move tens of thousands more dollars into tax-free growth each year, well beyond the $7,500 IRA limit. It’s a different mechanism than the regular backdoor Roth, with its own plan-design requirements and its own traps.

By Richard Zangara, Founder & Managing Director, IvyCrest Private Wealth & Partners · LinkedIn

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Why This Matters Now

In an earlier piece, we walked through the “backdoor Roth,” the two-step move that lets high earners fund a Roth IRA despite being priced out of contributing directly. (If Traditional and Roth IRAs aren’t a familiar distinction to begin with, our quick reference on the basics covers that first.) That strategy is capped by the IRA contribution limit: $7,500 in 2026, $8,600 if you’re 50 or older. For a lot of the executives and business owners we work with, that ceiling is almost beside the point relative to what they’re actually capable of saving.

If your 401(k) plan happens to allow two specific features (after-tax contributions beyond the normal deferral limit, and either in-service withdrawals or in-plan Roth conversions), there’s a related strategy that can move dramatically more money into tax-free growth every year. It’s commonly called the “mega backdoor Roth,” and depending on your plan design, it can mean tens of thousands of additional dollars in Roth space annually, not thousands.

This isn’t available in every workplace plan, and business owners who sponsor their own 401(k) have a decision to make that employees at a large company don’t: whether to design the plan to allow it in the first place. That’s worth knowing whether you’re the employee asking HR a question, or the owner deciding what your own plan should offer.

How the Mega Backdoor Roth Actually Works

Three Layers of 401(k) Contribution Limits

A 401(k) actually has more room in it than most people realize, once you look past the number most people know:

• Employee deferral limit: $24,500 in 2026 ($32,500 if you’re 50 or older, or $35,750 if you’re 60 to 63). This is the pre-tax or Roth 401(k) amount most people think of as “the 401(k) limit.”
• Overall plan limit: $72,000 in 2026 ($80,000 including catch-up contributions, or up to $83,250 for those age 60 to 63). This is the combined ceiling on your deferrals, any employer match or profit-sharing contribution, and after-tax contributions, all added together.
• The gap between those two numbers, after subtracting whatever your employer contributes on your behalf, is the room available for additional after-tax contributions. That gap is what the mega backdoor Roth strategy uses.

The Two Requirements

• Your plan must allow after-tax (non-Roth) contributions above the standard deferral limit. This is a separate contribution type from both pre-tax and Roth 401(k) deferrals.
• Your plan must allow either in-service withdrawals of that after-tax money (so it can be rolled to a Roth IRA while you’re still employed) or in-plan Roth conversions (so it can be moved into the Roth 401(k) bucket within the same plan).
• Not every 401(k) offers either feature, let alone both. This is fundamentally a plan-design question, not something available by default. Checking with your plan administrator, or your own plan document if you’re the business owner, is the necessary first step.

Why Speed Matters Here

Unlike the IRA version of the backdoor Roth, the after-tax contribution here sits inside a 401(k) that’s actively invested, so it can generate earnings between the time you contribute and the time you convert. Those earnings are taxable when converted. Only the original after-tax contribution moves tax-free. That’s why people using this strategy tend to convert frequently (some plans allow automatic quarterly or even per-paycheck conversions) rather than letting after-tax dollars sit and grow before moving them.

2026-Specific Considerations

• Contribution ceiling: The overall 401(k) limit for 2026 is $72,000 ($80,000 with the standard catch-up, or $83,250 for those 60 to 63). After backing out your own deferrals and any employer contribution, that’s the maximum room for after-tax contributions in a single year.
• A new wrinkle from SECURE 2.0: starting in 2026, anyone 50 or older whose prior-year wages from their employer exceeded $150,000 must make any catch-up contributions on a Roth basis rather than pre-tax. It doesn’t change the mega backdoor Roth mechanics directly, but it’s part of the same broader shift toward more of a high earner’s retirement savings landing in Roth space by default, and it belongs in the same conversation.
• Nondiscrimination testing: because after-tax contributions above the deferral limit are subject to IRS nondiscrimination rules (the ACP test), a plan can’t let only owners and executives use this feature. Broad-based participation, or a safe harbor design, generally has to be in place for it to hold up.
• Plan design is a live decision for business owners: if you sponsor your own 401(k), whether to add after-tax contributions and in-service withdrawal provisions is something you (with your plan’s third-party administrator) can actually choose to do. This isn’t fixed the way it is for an employee at a large company.

Which Path Fits Your Situation?

Consider a Mega Backdoor Roth If…

• You’ve already maxed out your regular 401(k) deferral and still have significant cash flow available to save
• Your plan already allows after-tax contributions and in-service withdrawals or in-plan conversions, or you, as the business owner, are willing to add those features
• You want meaningfully more in Roth space than the $7,500 IRA-based backdoor Roth alone can provide

Consider Other Options If…

• Your plan doesn’t currently allow after-tax contributions or in-service withdrawals, and amending the plan isn’t realistic this year
• You haven’t yet maxed out your standard 401(k) deferral or captured your full employer match. That comes first
• As a business owner, the nondiscrimination testing or added plan administration cost of offering this feature outweighs the benefit for your specific employee population

Additional Factors Worth Weighing

In-Service Withdrawal vs. In-Plan Conversion

An in-service withdrawal moves after-tax money out of the 401(k) entirely and into a Roth IRA you control. It’s generally the more flexible destination, since it isn’t tied to your employer’s plan menu. An in-plan Roth conversion instead moves the money into the Roth 401(k) bucket within the same plan, which some plans handle automatically (even every payroll cycle) but which leaves the money subject to that plan’s investment options and any future employer changes to the plan.

How This Differs From the Regular Backdoor Roth

The two strategies solve a similar problem through different accounts entirely. The regular backdoor Roth runs through an IRA and is capped at the IRA contribution limit, while the mega backdoor Roth runs through a 401(k) and is capped at the much larger overall plan limit. They aren’t mutually exclusive: many of our clients use both in the same year, one through their IRA and one through their workplace plan, each subject to its own separate limit.

Nondiscrimination Testing, for Business Owners

After-tax contributions above the deferral limit are treated as “employee contributions” for IRS nondiscrimination testing purposes (the ACP test), which compares participation rates between highly compensated employees and everyone else. A safe harbor plan design can simplify or eliminate this testing. Discuss it directly with your plan’s third-party administrator before assuming the feature is either easy or impossible to add.

Reporting

• A conversion or in-service withdrawal generates a Form 1099-R from the plan, generally issued the following year.
• Only the after-tax contribution amount converts tax-free. Any earnings that accrued before conversion are taxable in the year converted, which is the main reason frequent, small conversions are generally preferred over large, infrequent ones.

The Five-Year Rule Still Applies

As with any Roth conversion, converted mega backdoor Roth funds are subject to their own five-year holding period for penalty-free withdrawal of the converted amount before age 59½. That’s the same rule that applies to a standard Roth conversion, tracked separately for each conversion.

Call to Action

Whether your plan already supports this, or you’re a business owner deciding whether it should, this is the kind of plan-design and cash-flow question best mapped out with someone who can see the whole picture.

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Related Reading

• New to Traditional and Roth IRAs? See Traditional IRA vs. Roth IRA: The Basics
• Haven’t maxed out the IRA-based version yet? See Backdoor Roth IRA Contributions
• Sitting on unused 529 college savings? See 529-to-Roth IRA Rollovers

Sources

1. Internal Revenue Service, “Retirement Topics: 401(k) and Profit-Sharing Plan Contribution Limits.” irs.gov
2. Internal Revenue Service, “Retirement Topics: Catch-Up Contributions.” irs.gov
3. Charles Schwab, “What Is a Backdoor Roth IRA? Income Limits, Taxes, and Rules” (mega backdoor Roth FAQ), June 11, 2026. schwab.com
4. NerdWallet, “Mega Backdoor Roths: How They Work, Annual Limits.” nerdwallet.com
5. Bankrate, “What Is a Mega Backdoor Roth?” bankrate.com

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Securities and advisory services offered through &Partners LLC, member FINRA/SIPC. This article is for general informational purposes only and does not constitute tax, legal, or individualized investment advice. Consult your tax advisor regarding your specific situation.