Abstract: A copolymer of ethylene and hydrolysable silane includes from 0.1 wt % to 5.0 wt % hydrolysable silane groups and has a Mz(abs)/Mw(abs) of less than or equal to 9.5; a ratio of Mz(abs)/Mw(abs) to polydispersity of less than or equal to 1.5; a polydispersity of 6.6 or greater; a Density×Polydispersity of 6.0 or greater; or an Amorphous Content at Room Temperature×Polydispersity of 360 or greater. Methods for forming a moisture-crosslinkable polymer composition include forming a copolymer of ethylene and hydrolysable silane at a polymerization temperature of greater than or equal to 180° C. to less than or equal to 400° C. at a pressure from 5,000 psi to 50,000 psi; and adding a silanol condensation catalyst to the copolymer of ethylene and hydrolysable silane.