Top quark production at future lepton colliders in the asymptotic regime

The production of a $t\overline{t}$ pair from lepton-antilepton annihilation is considered for values of the center of mass energy much larger than the top-quark mass, typically of a few TeV size. In this regime a number of simplifications occur that allow us to derive the leading asymptotic terms of various observables using the same theoretical description that was used for light quark production. Explicit examples are shown for the standard model and the minimal supersymmetric standard model cases.