The views herein are personal, and indeed hypothetical to the author. They are US-centric but do not represent the view of the US Commodity Futures Trading Commission, any Division or Office of that Commission or of any other person, nor are they intended to reflect an analysis of any matters pending before the Commission. This paper is written from the perspective of the US financial services regulatory system, which has a history of mandated self-regulation and which recognizes exchange and independent self-regulatory authorities. It is intended to pose a challenge to the current discussion about how best to oversee the operation of exchanges as market structure evolves.