2026 Retirement Plan Limits and the Mega Backdoor Roth: Making the Most of a Tech 401(k)
Updated: Sep 21
Higher contribution limits and generous plan features at many Bay Area employers create room to shelter far more than the headline 401(k) number.
Each fall the IRS adjusts retirement plan contribution limits for inflation, and for 2026 the numbers moved up meaningfully. For high-earning technology professionals, the headline employee deferral limit is only the beginning. Many Silicon Valley employers offer plan features that, used together, can allow well over $70,000 per year of tax-advantaged savings.
The 2026 numbers
According to the IRS announcement for 2026:
The employee deferral limit for 401(k), 403(b), and most 457 plans is $24,500, up from $23,500.
The catch-up contribution for participants age 50 and older is $8,000, up from $7,500.
The enhanced catch-up for participants ages 60 through 63 remains $11,250.
Beginning in 2026, if your prior-year wages from your employer exceeded $150,000, any catch-up contributions must be made as Roth (after-tax) contributions, a change required by the SECURE 2.0 Act, according to the IRS.
The IRA contribution limit is $7,500, with a $1,100 catch-up for those 50 and older.
Roth IRA eligibility phases out between $153,000 and $168,000 of modified adjusted gross income for single filers and $242,000 to $252,000 for married couples filing jointly.
The overall limit on total annual additions to a defined contribution plan, which includes employee deferrals, employer contributions, and after-tax contributions, is $72,000 for 2026, up from $70,000, according to IRS Notice 2025-67. Participants 50 and older can add their catch-up contribution on top of that figure.
Pre-tax versus Roth deferrals
Most plans allow you to designate deferrals as traditional (pre-tax) or Roth (after-tax, with tax-free qualified withdrawals). The general principle is to pay tax when your rate is lower: pre-tax deferrals tend to win when your tax rate today is higher than your expected rate in retirement, and Roth deferrals tend to win when the reverse is true. For a Bay Area employee in the 35% or 37% federal bracket plus California rates of up to 13.3% (a 12.3% top bracket plus a 1% Mental Health Services Tax on taxable income over $1 million, per the California Franchise Tax Board), pre-tax deferrals offer a large immediate benefit. On the other hand, someone who expects to retire in a lower-tax state, or who values tax diversification, may prefer to build some Roth assets. Many people split the difference.
The mega backdoor Roth
The mega backdoor Roth is a strategy available only if your plan permits two features: after-tax (non-Roth) contributions and either in-plan Roth conversions or in-service distributions of after-tax money to a Roth IRA. Many large technology employers in the Bay Area offer both.
The mechanics are simple in concept. After you max out your $24,500 deferral and your employer adds its match, the remaining room under the $72,000 overall limit can be filled with after-tax contributions. Those contributions are then converted to Roth, either within the plan or by rolling them to a Roth IRA. Because the money was already taxed, the conversion itself generates little or no additional tax, and future growth is tax-free if the qualified distribution rules are met. Mercer Advisors' summary of 2026 limits illustrates that a participant under 50 with no employer match could contribute up to $47,500 in after-tax dollars in 2026.
Points to keep in mind:
Convert promptly. Earnings on after-tax contributions are taxable when converted, so many plans allow automatic conversion at each payroll.
Check for plan testing limits. Highly compensated employees may have after-tax contributions restricted if the plan fails nondiscrimination testing.
Coordinate with the regular backdoor Roth. Rolling pre-tax IRA money into your 401(k) can clear the way for a clean backdoor Roth IRA contribution by avoiding the pro-rata rule that applies to IRA conversions reported on Form 8606.
Health savings accounts
If you are enrolled in a qualifying high-deductible health plan, an HSA adds another layer. For 2026, contribution limits are $4,400 for self-only coverage and $8,750 for family coverage, according to IRS Revenue Procedure 2025-19, and Fidelity notes an additional $1,000 catch-up at age 55. Contributions are deductible federally, growth is tax-free, and withdrawals for qualified medical expenses are tax-free. California does not conform to federal HSA tax treatment, so contributions and earnings are taxable on your state return.
Putting it together
A Silicon Valley employee under 50 who fully uses a 401(k) with mega backdoor capability, a backdoor Roth IRA, and a family HSA could shelter more than $85,000 in a single year. Whether that is appropriate depends on cash flow, other goals such as a home purchase, and the need for accessible savings. This article is educational only and is not investment or tax advice; plan features vary by employer, so review your summary plan description and consult a qualified professional.
Sources
Links accessed September 2026.
Important Disclosures
Important Disclosures: Propulsion Capital Management is an investment adviser registered with the State of California Department of Financial Protection and Innovation. Registration does not imply a certain level of skill or training. This article is provided for general informational and educational purposes only and does not constitute investment, tax, legal, or accounting advice, nor an offer or solicitation to buy or sell any security or to adopt any particular investment strategy. The information is believed to be accurate as of the date of publication but is subject to change without notice; tax laws and regulations change frequently and their application depends on individual facts and circumstances. Nothing herein should be relied upon as a substitute for personalized advice from a qualified professional. Investing involves risk, including the possible loss of principal, and past performance is no guarantee of future results. Diversification does not ensure a profit or protect against loss. Any examples are hypothetical, are for illustrative purposes only, and do not reflect the experience of any client. Links to third-party websites are provided for convenience; Propulsion Capital Management does not endorse, and is not responsible for, the content of third-party sites. Propulsion Capital Management does not provide tax or legal advice; please consult your tax adviser or attorney regarding your specific situation.
