What does a plan sponsor due in this situation?

A few years back, salary deferrals for one pay period were not deposited timely to the 401(k) trust. Upon discovery the sponsor made the contribution to the trust, and filed form 5330 to pay the excise tax on the "amount involved" (the assumed interest on the assumed loan). BUT, the sponsor forgot to deposit the related lost earnings to the plan associated with the late deposit.

It seems clear under DFVC principles, that the lost earnings, plus earnings on the lost earnings are still due to the plan. But, is there a new or recurring prohibited transaction excise tax because the original error has not been fully corrected?

DFVC has to do with late filing of Form 5500.

You are going to have to file a 5330 for each year earnings were not deposited and for the year the earnings were deposited. This will include earnings on earnings as you mentioned.

Thanks. That's what I was afraid of.

(And I meant VFCP not DFVC. I was thinking the right letters but the fingers typed out the wrong ones. Too late in the week to keep the alphabet soup straight!)