Higgs-boson-mediated FCNC in supersymmetric models with largetanβ

In the supersymmetric models with a nontrivial flavor structure in the soft-breaking sector the exchange of neutral Higgs bosons mediates $\Delta F=2\mathrm{}$ transitions. This mechanism is studied for $\Delta S,\Delta B=2\mathrm{}$ processes and for a generic form of the soft-breaking terms. We find that Higgs-boson-mediated FCNC amplitudes increase very rapidly with $\tan \beta$ and can exceed SUSY box contribution by up to two orders of magnitude when $\tan \beta \sim m_t{/m}_b.$