fidelity solo 401k question

[DMdoc]

For those with a Fidelity solo 401k, how do you designate that the employER contribution is to the prior year and not the current year. For example, I am contributing part of my 2017 contribution (as the employER) now and plan to put in the rest closer to tax time. I cannot figure out how to do the designation on the paper form you have to fill our for the deposit. Or does it even matter as long as I keep track on my end?

Thanks!

[spiritrider]

Fidelity is doing you a favor here. It is actually better if you do not designate the year of a 401k employer contribution to a custodian. Then the operative record of the contribution year for contributions up until your tax filing deadline including extensions is based on which tax year you claim the deduction for.

Then if you find when you actually complete and file your taxes that you have contributed too much. You simply file your taxes with the reduced deduction and the contribution is automatically attributed to the following year.

This is important because 401k excess employer contributions can not generally be returned, there is a 10% excise tax and 401k plan filings required.

[DMdoc]

Thank you so much! That makes sense now.

Now if only I didn't have to write a check and snail mail it to them...

[childay]

My understanding is they don't do anything with that form.  It's mainly for your record-keeping.