High-Income Earner Shelters $69K/Year via Backdoor and Mega Backdoor Roth

The Problem

This client was a pharmaceutical company vice president earning $550,000 in total W-2 compensation including base salary, bonus, and deferred compensation payouts. The client was contributing $23,500 to the employer's traditional 401(k) but had been told by the HR benefits team that "Roth IRAs are not available to people at your income level" due to the $240,000 MAGI phase-out for Roth IRA contributions. The client's CPA confirmed this without mentioning the backdoor Roth strategy.

The client was also unaware that the employer's 401(k) plan allowed after-tax contributions above the $23,500 employee deferral limit, up to the IRC §415(c) total annual addition limit of $70,000 (for 2026). These after-tax contributions could be converted to Roth through an in-plan Roth conversion (the "mega backdoor Roth"), creating up to $46,500 per year in additional Roth retirement savings. Between the missed backdoor Roth IRA and the unused mega backdoor Roth 401(k), the client was leaving approximately $53,500 in annual Roth contribution capacity unused.

AE Tax Strategy

1. Backdoor Roth IRA Strategy Under IRC §408A

We implemented the backdoor Roth IRA strategy: the client contributed $7,000 to a traditional IRA (non-deductible, since AGI exceeded the deduction threshold) and immediately converted the balance to a Roth IRA. Because the contribution was non-deductible and the client had no other traditional IRA balances (we had previously rolled an old traditional IRA into the employer 401(k) to avoid the pro-rata rule under IRC §408(d)(2)), the conversion triggered zero taxable income. This produced $7,000 in annual Roth contributions that will grow and be distributed entirely tax-free in retirement.

2. Mega Backdoor Roth via After-Tax 401(k) Contributions Under IRC §415(c)

We worked with the client's HR team to confirm the 401(k) plan permitted after-tax employee contributions and in-plan Roth conversions. The client increased after-tax contributions to fill the gap between the $23,500 pre-tax deferral plus $16,500 employer match ($40,000 total) and the $70,000 IRC §415(c) limit, adding $30,000 in after-tax contributions. Each pay period, after-tax contributions were automatically converted to the Roth 401(k) sub-account through the plan's in-plan Roth conversion feature, minimizing any taxable earnings on the after-tax balance before conversion.

3. HSA Maximization and Tax-Free Growth Coordination Under IRC §223

In addition to the Roth strategies, we enrolled the client in the employer's High Deductible Health Plan (HDHP) with a Health Savings Account (HSA). The client contributed the family maximum of $8,550 to the HSA — deductible above the line regardless of AGI, invested in a diversified portfolio for long-term growth, and used out-of-pocket for current medical expenses while saving HSA receipts for future tax-free reimbursement. The HSA effectively serves as a triple-tax-advantaged retirement account: deductible going in, tax-free growth, and tax-free withdrawals for qualified medical expenses. Combined with the backdoor Roth ($7,000), mega backdoor Roth ($30,000), pre-tax 401(k) ($23,500), and HSA ($8,550), total annual tax-advantaged contributions reached $69,050.

Before & After Comparison

Tax Category	Before	After	Savings
Pre-Tax 401(k) Deferral	$23,500	$23,500	$0
Backdoor Roth IRA	$0	$7,000	$7,000
Mega Backdoor Roth 401(k)	$0	$30,000	$30,000
HSA Contribution	$0	$8,550	$8,550
Total	$23,500	$69,050	$69,000 (annual tax-advantaged contributions)

Key Takeaways

• The backdoor Roth IRA strategy is available to high-income earners regardless of MAGI — the income limits only apply to direct Roth IRA contributions, not to conversions from traditional IRAs.
• The mega backdoor Roth requires an employer plan that permits after-tax contributions and in-plan Roth conversions — not all plans offer this, but it is increasingly common among large employers.
• The pro-rata rule under IRC §408(d)(2) can torpedo backdoor Roth conversions if the taxpayer has existing traditional IRA balances — rolling old IRAs into the employer 401(k) before converting is essential.
• HSAs offer triple-tax benefits that exceed even Roth accounts: deductible contributions, tax-free growth, and tax-free withdrawals for qualified medical expenses at any age.