  Extrapolating the tau and b masses in the MSSM tends to give for their ratio
at the GUT scale a number around 1.2, for most viable values \tan \beta, rather
than the minimal SU(5) prediction of 1. We suggest that this may be due to
large off-diagonal elements in the charged lepton mass matrix M_L that can also
explain the large atmospheric neutrino mixing angle. Several simple models with
definite predictions for m_{tau}/m_b(M_{GUT}) are presented.
