Paying plan fees with plan assets

Thank you as always for the insights and knowledgeable responses. A portion of a Plan's assets were discovered as unclaimed funds and returned to the plan sponsor. This was done by a company that specializes in finding unclaimed funds, and this company is charging a fee (commission) for finding these assets. Can plan assets be used to pay this fee? Is this considered a settlor  or a non settlor expense? Thank you.

Were assets “returned” to the sponsor or the plan? How were the funds unclaimed? I realize that my questions are not directly in line to answer your question. The circumstances are quite curious. If plan assets were somehow “unclaimed” it may suggest breach of fiduciary duty at some time. In my limited experience with unclaimed funds bounty hunters (not involving any plan) one should consider an independent search for funds after being first approached by the bounty hunter, but it sounds like that time has passed. Circumstances dictate appropriate responses and the circumstances of unclaimed plan funds is a new one on me. Or maybe I misunderstand what you are describing.

Generally, administrative expenses paid from the plan are for routine administrative services like recordkeeping, compliance, 5500s, investment monitoring, and plan audit.

This does not sound like an administrative service, and if the plan sponsor had engaged search company to retrieve the unclaimed assets, that would seem to be more of a settlor expense (basically CYA for not being a diligent fiduciary).  Just an opinion.

Did the search firm provide any information about the potential source of the unclaimed funds?  Were they attributable to a dormant account in the name of the plan? Or, possibly were they in a bank account that was used to pay distributions and amounts from uncashed checks were redeposited?  Were they attributable to a litigation settlement and put into an account that was otherwise ignored?

When the assets were returned to the plan sponsor, what was deposited into the plan's trust - full amount of what was missing, the net amount after the search company fee, or nothing (the plan sponsor kept it)? 

The answers likely will lead to a host of other questions.

this is iffy as suggested by OP.  IMHO, the answer resides in the future use of the assets discovered.  Will the money be used to benefit the participant (after the fees paid)?  If yes, then it MIGHT be paid from the trust.   Will the money revert to the Employer?  If no, then it is more of a settlor function.

Thank you all. It is much appreciated. The money will be given to the  participant, the owner, who was the only participant in the plan at that time.