  Supersymmetric (SUSY) theories are often thought to give large branching
ratios for $b \rightarrow s \gamma$ from charged Higgs loops. We show that in
many cases chargino loop contributions can cancel those of the Higgs, and SUSY
can give $B(b \rightarrow s \gamma)$ at or below the \SM\ prediction. We show
this occurs because the large stop mass splittings usually found in SUSY break
a GIM mechanism suppression. These effects are strongly enhanced by large
$\tan\beta$, so that $B(b \rightarrow s \gamma)$ is very sensitive to the value
of $\tan\beta$, contrary to what has been claimed. We also note that the
supergravity relation $B_0 = A_0-1$ is somewhat disfavored over the general
case.
