Question

Forgot to file 1099-r for mega backdoor 401k

Forum|Forum|3 years ago
February 19, 2023
2 replies
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Hi everyone! I forgot to file my 1099-R for my after-tax 401k -> Roth 401k conversion (mega backdoor) for my previous year's tax return. Can anyone help me figure out which forms I need to file/steps I need to take? Luckily, I used TurboTax so hopefully, it'll be easy.

Thank you so much in advance!

TurboTax Premier Online

T

taxesohbotherAuthor

Whoops, OP here. Forgot to add that the taxable amt in box 2a was $0.01 and box 7 code is G. I'm just concerned that in my previous 1040, line 5a Pensions and Annuities and 5b are blank.

M

MAK70

You will need to file a Form 8606 to show the nondeductible contributions. You can file it for a prior year without amending your tax return, but it is best to enter in TurboTax so that it is pulled forward each year. See How to File an Amended Tax Return with the IRS - TurboTax.

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taxesohbotherAuthor

Hi Maryk4, thanks for the response—but isn't Form 8606 only for the backdoor (traditional IRA -> Roth IRA conversion) and not the mega backdoor (after tax 401k -> Roth 401k conversion)?