My Solo 401k Financial clients also have the option to convert their voluntary after-tax solo 401k funds held in a non-prototype brokerage account at Fidelity Investments to their Vanguard Roth IRA. The following video and procedure detail the following:
- How to open a mega backdoor Roth solo 401k with My Solo 401k Financial;
- How open the solo 401k non-prototype brokerage accounts at Fidelity Investments;
- How to convert the voluntary after-tax solo 401k funds from Fidelity Investments to the Roth IRA at Vanguard; and
- How to report the non-taxable conversion of voluntary after-tax solo 401k funds to the Vanguard Roth IRA.
- Video Slides: Mega Backdoor Fidelity Roth Solo 401k to Roth IRA at Vanguard
Conversions are reported in the year that the funds are actually moved over to the Roth account.
The solo 401k contribution rules are different from the conversion rules. Contributions can be made by your business tax return due date plus any timely filed extension for the prior year.
In sum, the voluntary after-tax solo 401k conversion will be nontaxable regardless if you convert the after-tax contributions that were made in 2021 or in 2022 for 2021.