Reporting structure for IA

For those IA departments that report functionally to the Supervisory Committee and administratively to the CEO:  I'm looking for how you define 'functionally' vs 'administratively'.  What is the Supervisory Committee responsible for and what is the CEO responsible for?       If you use another reporting structure, what is it and how are responsibilities defined?      Does it work well?       Please include your CU asset size in your response.     Thanks!     Lorraine