Do I need to add my workplace's 401k assets to my solo 401k's assets to determine if I need to file form 5500? What about my IRAs, are those "one participant plans"?

[medium0]

Workplace is my 9 to 5 job with standard 401k plan. I also have a solo 401k for my freelance work. And I have my IRAs. I think I just need to make sure that any solo 401k assets (I only have 1 solo 401k) are under $250,000 and I don't need to file form 5500, but not 100% sure. Do IRAs not count as "one participant plans"?

[Critter]

Each individual 401K plan will file it's own 5500 form ... you do not add them together.  Ask the plan administrator for assistance as they usually file those forms for you. 

[medium0]

Agree that file 5500 for each solo 401k, but what about: 

From Form 5500-EZ instructions:
"You do not have to file Form 5500-EZ for the 2019 plan year for a one-participant plan if the total of the plan's assets and the assets of all other one-participant plans maintained by the employer at the end of the 2019 plan year does not exceed $250,000, unless 2019 is the final plan year of the plan."

I'm pretty sure this is talking about if I had 2+ solo 401ks (say I had 2+ totally different businesses), but just making sure "other one-participant plans" can't mean IRAs. (Though now I am pretty sure it doesn't apply to my 9 to 5 401k since that 401k plan is maintained by that employer, not me, and it's not a one-partcipant 401k, but a normal company-wide type one.)

[dmertz]

Yes, the Form 5500-EZ is taking about combining multiple plans of a single employer.  Do not combine with your plan assets at a different employer.