A controlled conversion resin having an epoxy functionality of greater than 2 and comprising moieties derived from epoxy resin, dihydric phenol, acid anhydride, or amine. The resin is prepared by reacting an epoxy resin with a dihydric phenol, an acid anhydride, or amine or other branching agent in the presence of a catalyst and terminating the reaction at a point such that the reaction product contains both epoxy and terminal hydroxyl groups.