A Mega Backdoor Roth is an advanced retirement strategy that allows individuals to contribute significantly more to a Roth IRA or Roth 401(k) than the standard limits. It involves two steps: (1) making after-tax contributions to a 401(k) plan; and (2) converting those contributions to Roth, either within the 401(k) or by rolling them into a Roth IRA.
When you do these two steps simultaneously, there is no gain to report. But if the after-tax contribution is made and the Roth conversion occurs at a later date, there is potentially a gain to be reported.
We advise our clients that you should make this conversion simultaneously so you will not have to report any gain or loss. However, if a simultaneous conversion was not completed, the conversion could be subject to gain. This post will discuss how to calculate the gain.
What if I do a simultaneous conversion?
As noted above, making contributions to a Mega Backdoor Roth is really a two-step process. First, you need to make an after-tax contribution. Then you have to convert that amount into Roth.
Do I have a gain on conversion?
To calculate the gain on an in-plan rollover from after-tax contributions in a mega backdoor Roth, you need to determine the difference between the total amount of after-tax contributions you made to your 401(k) and the total value of those contributions (including earnings) at the time of the rollover. The gain is the taxable portion that needs to be reported on your tax return; essentially, it’s the total growth on your after-tax contributions within the plan before conversion to Roth status.
Key steps to calculate the gain
If you did not do a simultaneous conversion, you will need to complete the following steps in order to calculate the reported gain:
- Identify your after-tax contributions: Find the total amount of money you contributed to your 401(k) plan specifically designated as after-tax contributions.
- Determine the current value of your after-tax account: Check your 401(k) statement to see the current balance of your after-tax account.
- Calculate the gain: Subtract the total amount of after-tax contributions from the current value of your after-tax account. This difference represents the total gain accumulated on your after-tax contributions.
Important points to consider:
- Pro-rata rule: If your 401(k) contains both pre-tax and after-tax contributions, you might need to apply the pro-rata rule when calculating the taxable portion of your rollover, meaning a portion of the earnings on your pre-tax contributions may be considered taxable as well.
- Consult your plan administrator: Always check with your plan administrator to understand the specific details of your plan regarding in-plan rollovers and how to calculate the taxable gain on your after-tax contributions.
Example:
- You contributed $20,000 in after-tax contributions to your 401(k).
- The current value of your after-tax account is $25,000.
- Gain: $25,000 (current value) – $20,000 (contributions) = $5,000 taxable gain.
Final thoughts
This strategy leverages the total annual 401(k) contribution limit, which includes employee and employer contributions, to maximize savings. The Mega Backdoor Roth is especially advantageous for individuals who have already maxed out their traditional or Roth 401(k) contributions and want to save more in a tax-advantaged account for retirement. However, it requires a 401(k) plan that allows after-tax contributions and in-service withdrawals or in-plan Roth conversions.
