Thermally initiated cationic ring-opening polymerization of 3-ethyl-3-(hydroxymethyl) oxetane was carried out using benzyltetramethylenesulfonium hexafluoroantimonate as initiator. The resulting hydroxy-functional polyether was thoroughly analyzed by H-1 and C-13 NMR spectroscopy and found to have a hyperbranched architecture with a degree of branching of 0.4. The polyether was successfully employed as a multifunctional initiator for epsilon-caprolactone. Molecular weight measurements on the polyether showed a narrow molecular weight distribution analyzed by SEC and MALDI-TOF (1.3 and 1.4, respectively).