Plan adopted, no action - still effective?

401(k) Plan was adopted 1/1/20.

There have been no deposits through 6/30/22.

How long can a plan continue to be a plan without any actual plan activity?

I am getting pretty rusty on 4k plans as I haven't worked on one since 2012....

But do you have missed deferrals strikes me as a better question?

If the plan was adopted and people entered the plan they should have been given the ability to defer and it sounds like they haven't been give any such election.  Or am I not understanding something?  

Presumably the plan was offered but everyone said no. I think we had a plan like that years ago where a Dr. had a plan for his union employees and he had to maintain a deferral only 401(k) Plan for them. In that case it wasn't zero as I think 2 people put in de minimus contributions but when they left no one else ever signed up. The plan ran a number of years with no new contributions. But I think that was than 10 or more years ago that plan terminated.

Assuming you have a valid plan that is actually offered to the employees but no one ever signs up I believe you can keep it going as long as you want as long as you keep the Plan document up to date, give the participants any required notices and file the 5500.

I'm not sure why you'd want to as a Plan Sponsor but maybe there is some valid business reason for having a Plan that no one uses.

Under some States’ and cities’ play-or-pay laws, maintaining an employment-based retirement plan that allows elective deferrals is one of the ways an employer avoids a tax, civil penalty, or other financial consequence.

For some kinds of businesses, it’s not unimaginable that no employee elects a deferral.

Yet, an employer might prefer to maintain a plan indefinitely.

Thank you for your feedback, all interesting.

For this particular plan, it's a one-person company so no besides the owner was able to defer.