Mega Backdoor Roth for California Tech Employees

How the mega backdoor Roth works

A standard 401(k) limits employee contributions to $24,500 in 2026 (pre-tax or Roth). The IRS also sets a higher overall limit under §415(c) — $70,000 in 2026 — that covers all contributions to the plan: your deferrals, employer match, profit sharing, and after-tax contributions. The gap between $24,500 and $70,000 (minus whatever your employer contributes) is the space where the mega backdoor Roth lives.

The strategy works in two steps. First, you make after-tax (non-Roth) contributions to your 401(k) — these are dollars you've already paid income tax on, contributed beyond your regular pre-tax or Roth deferral. Second, you convert those after-tax dollars to Roth, either through an in-plan Roth conversion or by rolling them out to a Roth IRA while still employed (an in-service withdrawal). Once inside Roth, future growth is tax-free — and qualified withdrawals in retirement are tax-free at both the federal and California level.

The key insight: you are not avoiding income tax on the contributions themselves. You have already paid that tax. What you are doing is ensuring the investment growth on those dollars — which could compound for decades — is never taxed again. At California's 13.3% rate on retirement income, every dollar of Roth growth represents a meaningful future saving compared to a pre-tax 401(k) that will be taxed at ordinary income rates on withdrawal.

The 2026 contribution limits and calculating your capacity

Your after-tax contribution capacity is whatever remains of the §415(c) limit after your elective deferrals and employer contributions are subtracted. The calculation varies by company:

At companies with no employer match, the after-tax room is $70,000 − $24,500 = $45,500. At companies with generous match programs, it narrows. At companies that also make profit-sharing contributions, it narrows further — sometimes to the point where the mega backdoor contribution is very small. Confirm the exact numbers with your plan documents or benefits administrator before setting your contribution rate.

Employees age 50 and over can also use the catch-up contribution, raising the elective deferral limit by $7,500 to $32,000 in 2026. The §415(c) limit also rises for catch-up eligibles, to $77,500 — so the after-tax room does not shrink with catch-up contributions.

Two paths: in-plan conversion vs. in-service withdrawal

Once you make after-tax contributions, you have two options for getting the money into Roth status. Which path is available depends entirely on your employer's plan design — you cannot choose one if your plan does not offer it.

Most large tech company plans offer in-plan conversion. If yours does, the operationally simplest approach is to set contributions to auto-convert immediately — many platforms (Fidelity NetBenefits, Vanguard, Principal) allow this as a standing election that fires every pay period. The goal is to convert before earnings accumulate on the after-tax balance, minimizing the taxable conversion amount.

Why California makes Roth accounts more valuable, not less

The objection California-based employees raise most often: "I'm paying 13.3% on the money going in. Why would I lock that in when I could defer the tax with a traditional 401(k)?" The answer requires looking at both sides of the ledger.

A traditional pre-tax 401(k) contribution defers California income tax today. But California will collect it when you withdraw — at ordinary income rates on every dollar, regardless of whether it represents original contributions or decades of growth. There is no stepped-up basis in retirement accounts, no capital gains preference, and no California exemption for retirement income (unlike some other states). The state's 13.3% top rate applies to IRA distributions the same way it applies to a paycheck.

A Roth account flips this: you pay California tax on contributions today, but withdrawals in retirement — contributions and all the growth — are completely tax-free in California. The larger and longer the growth period, the more valuable this becomes.

The calculus does tilt toward pre-tax if you plan to leave California before retirement. If you expect to retire in Nevada, Texas, or Florida — where there is no state income tax — a pre-tax 401(k) lets you defer California's 13.3% today and pay 0% state tax on withdrawal later. Many California tech employees do eventually leave the state; if that is your likely path, the Roth vs. traditional decision for your regular contributions shifts toward traditional. For the mega backdoor Roth specifically, you have already paid California tax on the contributions either way — the question is only about future growth.

Which major tech companies offer the mega backdoor Roth

The mega backdoor Roth requires two specific plan features: (1) after-tax contribution capability and (2) either in-plan Roth conversion or in-service withdrawal. Both must be present. Plans change annually — always confirm current plan design in your Summary Plan Description or with HR benefits.

Company	After-tax contributions	In-plan conversion / in-service withdrawal	Notes
Google / Alphabet	Yes	Yes — in-plan conversion	Widely discussed; auto-conversion available via Fidelity
Meta	Yes	Yes — in-plan conversion	Confirmed by multiple employee reports; no ESPP, making this a primary benefit
Microsoft	Yes	Yes	50% match up to IRS deferral limit; reduces after-tax room
Apple	Yes	Yes	Plan allows both features; confirm current year details with HR
Amazon	Varies by plan	Check current plan	Plan design has changed; confirm with current benefits documentation
Nvidia	Check plan	Check plan	Rapid growth has changed benefits frequently; verify current SPD
Broadcom	Check plan	Check plan	Post-VMware acquisition plan integration — current design may differ from legacy plans
Salesforce	Check plan	Check plan	Plan offerings vary; check current Summary Plan Description

The pro-rata problem and how to avoid it

If you choose the in-service withdrawal path (rolling after-tax contributions to a Roth IRA), you may encounter the pro-rata rule if your plan comingles after-tax and pre-tax dollars in the same account. When you withdraw, the IRS treats the distribution as a pro-rata mix of after-tax and pre-tax money — meaning you cannot selectively pull just the after-tax portion. Tax is owed on the pre-tax share of each withdrawal.

Most large tech company plans keep after-tax contributions in a separate sub-account, which avoids the commingling problem. When rolling out, you simultaneously roll the after-tax principal to a Roth IRA and any earnings (which are pre-tax) to a traditional IRA. If your plan comingles, the in-plan conversion path is operationally cleaner. Ask your plan administrator whether after-tax contributions are tracked separately before choosing the in-service withdrawal route.

Mega backdoor Roth vs. ESPP: where to put the dollars

For most California tech employees, the priority order is: ESPP first (up to the $25,000 FMV limit, because the guaranteed discount return is hard to beat), then mega backdoor Roth with remaining cash flow. The ESPP generates a near-certain return from the discount; the mega backdoor Roth generates a deferred tax benefit from growth. Both are worth doing if the cash flow allows. The common Teamblind question — "ESPP or mega backdoor Roth?" — is often a false choice at higher income levels where both can be funded simultaneously with some adjustment to current spending.

Where they genuinely compete is for employees with tighter cash flow who cannot fund both. In that case, the ESPP discount is a guaranteed return captured today; the mega backdoor benefit accrues over decades. For someone planning to leave California before retirement, the mega backdoor calculus is further complicated by the "pay 13.3% today, escape it later" dynamic. Model it before assuming either dominates.