This invention relates to novel carboxyester-modified vinylic polymeric compositions and the process for preparing them. In particular, the invention relates to novel carboxyester-modified vinylic polymeric compositions which exhibit properties that make them useful as support resins for producing polymer latices which can be employed in the formulation of various water-based coatings and inks, particularly flexographic inks. More particularly, these carboxyester-modified vinylic polymeric compositions are produced by the addition polymerization reaction of vinylic monomers in the presence of adducts of hydroxyl-substituted fatty acids and carboxylic anhydrides.