From page S15 of the AA Service Manual:
An Upside-Down Organization
Alcoholics Anonymous has been called an upside-down organization because, as the structure chart shows, the groups are on top and the trustees at the bottom. Bill W. wrote in Concept I: “The A.A. groups today hold ultimate responsibility and final authority for our world services….” Then, in Concept II, Bill made it clear that the groups “delegated to the Conference complete authority for the active maintenance of our world services and thereby made the Conference… the actual voice and effective conscience for our whole Society.”