The present invention provides carboxy-terminated oligomeric polyester compositions useful in the preparation of "weatherable" polymeric materials, for example weatherable copolyestercarbonates. In one aspect the present invention provides an oligomeric polyester composition comprising structural units derived from at least one diacid, at least one diaryl carbonate and at least one diol. The structural units derived from the diacid are present in a molar excess of from about 10% to about 40% based on a ratio of moles of diacid-derived structural units to moles of diol-derived structural units present in the oligomeric polyester composition. The oligomeric polyester composition is further characterized by the presence of at least some phenoxy end groups.