I have a client who has a calendar year 401(K) Plan. My understanding was that they could not change mid-year to a safe harbor 401(k).

I am getting confused because when I research the issue, I am finding information that states that you can adopt a safe harbor 401(k) late as long as you:
1. have the current year testing method;
2. give an annual notice to employees that you MAY amend the plan to provide safe harbor non-elect contrib;
3. Amend 30 days before the end of the plan year;
4. Give a supplemental notice not later than 30 days prior to the end of the plan year that you have amended to a safe harbor.

1.401(k)-3(f)

Based on everything I've learned, I think I must be misinterpreting something and that you cannot change a 401(k) plan mid-year. Can someone please help me understand.
Thank you!

you left out, 'except in the case of a new plan, a plan year must be 12 months long'. otherwise, you have done an excellent job.
1.401k-3e1

Hi,
So then, we can change a 401(k) plan mid-year to be a safe-harbor - as long as we follow all these points?

Thank you so much - I've spent hours on this and just don't trust my findings.
Linda

Your apprehension is well-founded. How will you have a 12-month plan year if you change mid-year?

Ahh - maybe here's my problem.

The client has a 401(k) Plan currently. I was going to amend their current plan midyear and thought that since the original plan will be in affect for 12 months - that this would satisfy the 12 month rule.