The invention is a stabilizer composition for halogen-containing polymers, comprising a carrier material of the general formula Ca.sub.xAl.sub.2(OH).sub.2(x+2)HPO.sub.3.m H.sub.2O, wherein x is a number from 2 to 12 and m is a number from 0 to 12, and a salt of a halogen-containing oxy acid or a mixture of two or more such salts, at least one salt of a halogen-containing oxy acid being present in finely distributed form on the carrier material, to a process for the preparation thereof, and to the use thereof.