Is this a Master Trust

[Guest esi-jht]

Employer sponsors a 401k plan and a MPPP. The assets of both plans are held in one trust with an insurance company. I need to clarify if this insurance company meets the definition of a "regulated financial institution" as found in the F5500 instructions and the ERISA Regulations. A review of DOL Advisory Opinion 93-21A leads me to believe that the insurance company, may, in fact, be a "regulated financial institution" and I'm thinking I have to meet the F5500 filing requirements for a master trust. TIA.