I’ve been maxing out my after-tax 401(k) and converting it to a Roth for 2 years — is this a good strategy?

High earners are increasingly considering the mega backdoor Roth conversion strategy, allocating after-tax dollars to a 401(k) until the $72,000 limit for 2026, then converting it to a Roth. This approach offers tax-free growth, no required minimum distributions, and zero pro-rata rule complications compared to a taxable brokerage account.

The One Big Beautiful Bill Act made Roth conversions more predictable by locking in current income tax brackets. With $10.1 trillion in assets held in 401(k) plans as of year-end 2025, many workers participate in these plans. However, the standard limits may feel like a floor for top earners. A Roth IRA with a $7,500 after-tax contribution cap for 2026 does not significantly impact high earners' financial security.

The mega backdoor Roth conversion is a powerful alternative, allowing high-earning savers to accumulate tax-free wealth during retirement.