I have an established 401k plan with a per payroll safe harbor match. The owner has a control group of 5 companies, of which the largest/main company is the adopting ER. The other 4 don't participate but we use their census for testing.
The contact approached us yesterday to see if we can add one of the other companies as an adopting ER ASAP. Am I correct in assuming that because this is a safe harbor plan, they cannot do this for 2018 since it is already past October 1 (this is a 12/31 PYE)?
Thanks for your thoughts!