File Form 5500 to report information on the qualification of the plan, its financial condition, investments and the operations of the plan. Use the links on the right of this page to learn more about how to search for unclaimed retirement benefits and steps to take before contacting PBGC.Form 5500 is filed with the DOL and contains information about a 401(k) plan's financial condition, plan qualifications, and operation. Requirements for retirement plans. Search PBGC's two databases of retirement plans in the Missing Participants Program. 9 Months Before Retiring. The ERISA Form 5500 Filings database is the most popular service, free or premium, on FreeERISA.