Can they maintain both plans and the Safe Harbor start up at any time? Or like converting a 401(k) to Safe Harbor 401, does the sponsor have to wait until the beginning of the plan year?

Thanks

You cant have a SIMPLE if you accrue a benefit under another qualified plan. so since both require contributions it would be impossible to have both at the same time.

so they terminate the SIMPLE IRA and start up a safe harbor 401 mid year. any problems with such a strategy

thanks

i think i just found my answer: if they are actively particiapting in a SIMPLE IRA at any time during the plan year, they would have to wait until the next plan year to start up the safe harbor. true ?

very wise and well said indeed, you have answered your own question!