  The MSSM with a light right-handed stop and supersymmetric models with a
singlet whose vev is comparable to that of the SU(2)_W Higgs allow for a
strongly first-order electroweak phase transition even for a mass of the
lightest Higgs around 100 GeV. After a short review of the standard model
situation we discuss these supersymmetric models. We also compare perturbative
calculations based on the dimensionally reduced 3-dimensional action with
lattice results and present an analytic procedure based on an analogue of the
stochastic vacuum model of QCD to estimate the nonperturbative contributions.
