A light bottom squark in the MSSM

We study the compatibility of a light bottom squark M (150 GeV)). We then consider the renormalization group flow up to the Grand Unified scale. For most regions of the parameter space with a light sbottom we find directions in the scalar potential which are unbounded from below. Only a small window in gluino mass and tan β is consistent with all bounds. This is alleviated by a light gluino, which is however only marginally experimentally allowed.