The invention relates to the use of polymers which comprise, in copolymerized form, an α-olefin, at least one alkenyl ester and at least one ester of an α,β-unsaturated carboxylic acid with higher alcohols as an additive for fuel oils and lubricants and especially as a cold flow improver in fuel oils; to the fuel oils and lubricants additized with these polymers; and to additive packages comprising such copolymers. The invention also relates to quaternary and higher copolymers which comprise the abovementioned monomers in copolymerized form.