An economical lightweight looseleaf binder combines the functionality of a standard ring binder with easy-to-use characteristics of report covers. The cover is folded to define front and back panels as well as a spine portion, and additionally includes a crease at the longitudinal center line of the two ring assemblies which are both secured to the back panel. The ring assemblies include a series of hooks having complementary notched profiles which firmly engage one another when closed, yet may be easily disengaged through flexure of the cover. In one construction, the binder comprises a pressboard cover to which is attached a pair of plastic ring assemblies. The hooks are configured to permit filler sheets to lie flat and to facilitate transfer of sheets from one side to the other.