Sn(Oct) 2-catalyzed synthesis of hyperbranched poly(glycolide) copolymers with glycerol branching points in the backbone is possible via ring-opening multi-branching copolymerization (ROMBP) of glycolide and 5HDON (5-hydroxymethyl-1,4-dioxan-2-one). Using this strategy, well-defined and soluble branched polyesters with apparent molecular weights (Mn) in the range of 1300-2000 g mol(-1) and varying comonomer content (5HDON/glycolide = 30:70-70:30) were obtained. 2D NMR spectroscopy, thermal analysis and MALDI-TOF mass spectrometry confirmed the successful incorporation of both monomers and the resulting branched structure. Multiple end group functionality offers the possibility for further post-polymerization modification, rendering the materials interesting with respect to processing of PGA. Potential applications range from novel polyurethanes to biomedical purposes. (C) 2015 Elsevier Ltd. All rights reserved.