Higgs-mass dependence of the effective electroweak mixing angle $\sin^2\theta_{eff}$ at the two-loop level

The result for the Higgs-dependent electroweak two-loop bosonic contributions to the effective leptonic mixing angle of the $Z$-boson in the Standard Model is presented. Together with the previously calculated fermionic contributions it yields the complete dependence of $\sin^2\theta_{\rm eff}$ on the Higgs-boson mass $M_H$ at the two-loop level. Compared to the fermionic contributions, the bosonic contributions are found to be smaller, but large enough to induce a non-negligible modification of the $M_H$ dependence