"Multiemployer plan trustees have a fiduciary duty under ERISA to make sure the fund is receiving all employer contributions that are due, based on participants' hours worked. This means they must follow up when employers neglect to send their contributions on time (in other words, when they're delinquent). This also means trustees need to make sure that the correct amounts are received. If trustees neglect this fiduciary responsibility, they can be personally liable. They help fulfill this duty by having a payroll audit performed by a knowledgeable and experienced auditor."