  The pure leptonic decay B_s -> mu mu is strongly suppressed in the Standard
Model (SM), but can have large enhancements in Supersymmetry, especially at
large values of tanbe. New limits on this decay channel from recent LHC data
have been used to claim that these limits restrict the SUSY parameter space
even more than the direct searches. However, direct searches are hardly
dependent on tanbe, while BR(B_s -> mu mu) is proportional to tanbe^6. The
relic density constraint requires large tanbe in a large region of the
parameter space, which can lead to large values of B_s -> mu mu. Nevertheless,
the experimental upper limit on BR(B_s -> mu mu) is not constraining the
parameter space of the CMSSM more than the direct searches and the present
Higgs limits, if combined with the relic density. We also observe SUSY
parameter regions with negative interferences, where the B_s -> mu mu value is
up to a factor three below the SM expectation, even at large values of tanbe.
