  Top quark mass suppressed terms are calculated for the virtual amplitude for
Higgs production in gluon fusion at three-loop level, i.e. O(\alpha_s^3). The
method of asymptotic expansions in its automated form is used to evaluate the
first three non-vanishing orders in terms of M_H^2/M_t^2, where the first order
corresponds to the known results of the effective Lagrangian approach.
