Do you have to actually make SoloK contributions before filing?

[dandarc]

I'm not finding a clear answer to this with my googling, so I'm asking the forum. The deadline for actually funding the individual 401K is tax filing deadline plus extension - that I'm clear on.

What I'm not clear on is whether I can file my tax return before funding the account. Tax return is finished - I've got $28K to go on the 2018 SoloK, which I should be able to do no later than the end of May. Have already made 2018 IRA and HSA contributions, so this is the only outstanding item on 2018 taxes.

What I'd like to do is file for an extension, then file my federal (getting $2K refund) and state taxes (owe $2300 to 2 states this year due to changing jobs and moving), then finish funding the SoloK for 2018. One of those states is Maryland, and the sooner I can file that return, the less I will owe due to them charging penalties / interest even for a first year filer such as myself.

[uwp]

I am not an accountant, but I don't think you need to make the contribution before filing. 

My SoloK provider (Oppenheimer) doesn't even report the year of contribution to the IRS.  I actually called them for clarification this morning because I couldn't find on their site where to designate the year. 

You basically report it yourself on your taxes, and then, I assume if you got audited, you would have to prove to the IRS you made the contributions and how they correspond to each year.

[bacchi]

That's what I've always done if I have a refund due.

However, if you're funding 2018 from 2019 income, how will you fund for 2019?

[dandarc]

That's what I've always done if I have a refund due.

However, if you're funding 2018 from 2019 income, how will you fund for 2019?

If I'm done funding 2018 in May, then I have 7 months of 2019 income + 4 months (10 with extension) of 2020 income for 2019 contributions.

[DavidAnnArbor]

Yes you have to fund your solo 401k prior to filing your tax return.

My tax CPA brother always makes me do that.