Mega Backdoor Roth: The Complete Guide for Tech Professionals

01

The Strategy Most High Earners Don't Know They Have

If you're a tech professional earning $250,000 or more, you've probably been told you can't contribute to a Roth IRA. Your income is too high. The direct contribution limit phases out completely at $168,000 for single filers and $252,000 for married filing jointly in 2026.

What you may not know is that there's a strategy available in some employer plans that lets you contribute far more to Roth accounts than the standard limits, sometimes over $40,000 per year on top of your regular contributions. It's called the mega backdoor Roth, and it is one of the larger Roth contribution opportunities available under current rules.

02

The Mechanics: How It Actually Works

The standard 401(k) contribution limit in 2026 is $24,500 (plus $8,000 catch-up if you're 50+). That's the limit on your pre-tax or regular Roth 401(k) contributions. But the total 415(c) limit (the maximum that can go into your 401(k) from all sources combined) is $72,000 in 2026.

The gap between those two numbers (roughly $47,500) can potentially be filled with after-tax contributions to your 401(k). That's not the same as Roth contributions; it's a different bucket. After-tax contributions have already been taxed, but any growth on them is taxable when you withdraw.

Here's where the strategy comes in. If your plan allows in-service withdrawals or in-plan Roth conversions, you can convert those after-tax contributions to Roth immediately, before they generate any taxable growth. The result: you've just moved up to $47,500 into Roth, tax-efficiently, in a single year.

03

Does Your Plan Support It?

Not every 401(k) plan allows this. Two specific plan features are required:

1. After-tax contributions: Your plan must allow after-tax (non-Roth) contributions above your standard employee deferral limit.
2. In-service withdrawals or in-plan Roth conversions: Your plan must allow you to either roll those after-tax contributions to a Roth IRA (in-service withdrawal) or convert them to the Roth 401(k) option within the plan (in-plan Roth conversion).

Amazon, Microsoft, and Google plans have generally supported both features, which is why this strategy comes up often with tech professionals in the Seattle area. Plan features change, so confirm yours in your Summary Plan Description. Boeing's 401(k) plan has more restricted rules; I work through the specifics with Boeing employees on a case-by-case basis.

If you're not sure whether your plan supports this, the place to look is your Summary Plan Description (SPD), available from your HR portal or benefits administrator.

04

The Step-by-Step Process

Once you've confirmed your plan supports it, the execution is straightforward:

1. Max your standard pre-tax or Roth 401(k) contributions ($24,500 in 2026)
2. Elect to make additional after-tax contributions to your 401(k), up to the 415(c) limit
3. As soon as those contributions are posted, trigger an in-plan Roth conversion or in-service rollover to a Roth IRA
4. Repeat regularly; many people do this monthly or per paycheck to minimize the time after-tax money sits unconverted

The "as soon as possible" part matters. The longer after-tax money sits without being converted, the more growth it accumulates, and that growth is taxable at conversion. Converting quickly keeps the taxable gain minimal or zero.

05

Combined with Employer Match: The Full Picture

If your employer contributes a match, that counts toward the $72,000 total limit. Here's how the math typically looks for an Amazon or Microsoft employee with a standard employer match:

• Employee pre-tax/Roth 401(k): $24,500
• Employer match: approximately $6,000 to $10,000 (varies by plan)
• After-tax contributions available: $72,000 minus the above = roughly $37,500 to $41,500

That's $37,500 to $41,500 of additional Roth contributions per year, on top of your standard 401(k) deferrals. Over a full career, those after-tax dollars can keep compounding in a Roth, where qualified withdrawals come out tax-free. It can be a meaningful addition to your retirement savings, though actual results depend on your contributions, returns, and tax law and are not guaranteed.

06

Tax Implications to Understand

The strategy is clean, but there's one wrinkle worth understanding: at the time of conversion, only the growth on after-tax contributions is taxable, not the contributions themselves (you already paid tax on those). This is why converting quickly is important. If you make $4,000 in after-tax contributions and they earn $50 before you convert, only $50 is taxable. If you wait six months and they grow by $500, you owe tax on $500.

Qualified Roth distributions are generally tax-free. Rules for conversions, five-year periods and inherited accounts can differ. Review your circumstances with your tax professional.

07

Who This Strategy Makes Sense For

The mega backdoor Roth works best when several conditions are true:

• You're in a high tax bracket now and expect your retirement tax rate to be lower (or you want tax diversification)
• Your plan supports after-tax contributions and in-service conversions
• You have cash flow available above your standard 401(k) contribution
• You have enough time before retirement for Roth assets to compound

For many Amazon, Microsoft, and Google employees earning $250,000+, all four conditions apply. For high-earning professionals who are more conservative about current taxes, a partial implementation (using some of the after-tax space without maxing it) is also a valid approach.

08

Getting the Implementation Right

The biggest implementation mistake I see is inconsistency. People set up after-tax contributions but forget to trigger the conversion. Or they convert annually instead of monthly, accidentally generating taxable gains. The strategy works cleanly when it's automated and systematic.

I build this as a standing element of the annual planning process for my tech clients, alongside their RSU vesting schedule, ESPP elections, and quarterly estimated tax payments. It doesn't need to be complicated, but it does need to be deliberate.

If you want to see whether your specific plan supports this and what the numbers look like for your income level, schedule a discovery call with me. I'll confirm plan eligibility, run the numbers, and we'll have a clear answer by the end of the conversation.

*Alex Carter, SC Financial Group and LPL Financial are not affiliated with, endorsed by, or sponsored by Amazon, Microsoft, Google, Boeing, or any other employer named in this article. Employer benefit details are general descriptions; confirm specifics with your plan documents.

Tax figures and contribution limits cited reflect the 2026 tax year and are subject to change.

Securities and advisory services offered through LPL Financial, a registered investment advisor. Member FINRA/SIPC. Carter Financial Planning, SC Financial Group, and LPL Financial are separate entities. Carter Financial Planning and SC Financial Group are not registered as broker-dealers or investment advisors. This article is for educational purposes only and does not constitute investment advice.

Backdoor Roth: A Roth IRA conversion—sometimes called a backdoor Roth strategy—is a way to contribute to a Roth IRA when income exceeds standard limits. The converted amount is treated as taxable income and may affect your tax bracket. Federal, state, and local taxes may apply. If you're required to take a minimum distribution in the year of conversion, it must be completed before converting. To qualify for tax-free withdrawals, you must generally be age 59½ and hold the converted funds in the Roth IRA for at least five years. Each conversion has its own five-year period, and early withdrawals may be subject to a 10% penalty unless an exception applies. Income limits still apply for future direct Roth IRA contributions. Although this strategy has existed since 2010, the IRS has not officially commented or provided formal guidance on whether it violates the step-transaction rule. (When applied, this rule treats what are several different steps as if they were a single transaction for tax purposes.) Experts have mixed opinions on the likelihood of this happening, but the lack of a definitive ruling means there is some risk involved. If the IRS decides that the loophole is a violation, if restrictions do come into play at some point, they could require backdoor Roth converters to pay a penalty, or they might include a grandfather clause. There's no guarantee the backdoor Roth IRA strategy will always be available. Congress recently considered legislation that would have eliminated the backdoor option. As of now, the backdoor Roth IRA is still around, but no one can predict its future. If you use this backdoor Roth strategy solely to sidestep the earnings limits on Roth, you need to be aware of the risks and seek the counsel and support of a tax professional. • All or part of a backdoor Roth IRA conversion could be a taxable event. You may have to pay federal, state, and local taxes on converted earnings and deductible contributions. • Conversions could kick you into a higher tax bracket for the year. • You must observe a 5-year aging rule in order to be eligible for tax-free distributions. All information is believed to be from reliable sources; however, LPL Financial makes no representation as to its completeness or accuracy.