Requiring the soft supersymmetry-breaking (SSB) parameters in finite g
auge-Yukawa unified models to be finite up to and including two-loop o
rder, we derive a two-loop sum rule for the soft scalar masses, It is
shown that this sum rule coincides with that of a certain class of str
ing models in which the massive string states are organized into N = 4
supermultiplets. We investigate the SSB sector of two finite SU(5) mo
dels. Using the sum rule which allows non-universality of the SSB term
s and requiring that the lightest superparticle is neutral, we constra
in the parameter space of the SSB sector in each model. (C) 1998 Elsev
ier Science B.V.