The invention relates to a process for the manufacture of a waterborne multistage polymer dispersion that has ethylenically unsaturated functional groups for crosslinking. The process comprises the steps of; a. making an aqueous emulsion or solution of a first stage polymer comprising carboxylic acid functionalized monomers to an amount sufficient to make the first stage polymer water soluble or dispersible, b. at least partially neutralizing the first stage polymer with a base, c. forming a two-stage polymer dispersion by adding to the at least partially neutralized first stage polymer a second stage monomer mixture and emulsion polymerizing said second stage monomer mixture to a second stage polymer which is less hydrophilic than the first stage polymer, d. reacting with the obtained two-stage polymer dispersion a bi-functional compound comprising an ethylenically unsaturated group and a group reactive towards the carboxylic acid in the two-stage polymer. The invention further relates to a water-borne curable multistage polymer dispersion, to coating compositions.