2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/44459The evaluation of the two-loop MSSM-contributions to the electroweak precision observables M_W and s_w^eff at order(alpha_t^2), order(alpha_t alpha_b), order(alpha_b^2) is presented. These contributions enter via Delta(rho), and it is explained in detail how one can retain the true, non-vanishing value of the MSSM Higgs boson mass M_h in spite of using the gauge-less limit in the calculation. The numerical results can be sizeable, in particular for strong squark mixing. By comparing the results in the on-shell and DR-bar renormalization schemes, the remaining theoretical uncertainty is found to be small.Talk given by D.S. at the 2005 International Linear Collider Workshop - Stanford, USA. 6 pages, 5 figures, misprint correctedHigh Energy Physics - Phenomenologytext