A stabilizer composition having low volatility and high efficiency comprising: (i.) 25.000% to 99.997% by weight of at least one dimethyltin compound of formula (CH3)2Sn(S(CH2)mCOOR1)2 wherein R1 is a linear, branched or cyclic C10-C20 alkyl group and m is 1 or 2, optionally containing unsaturations in the form of double or triple bonds; (ii.) 0.001% to 50.000% by weight of at least one mono-methyltin compound of formula CH3Sn(S(CH2)nCOOR2)3 wherein R2 is a linear, branched or cyclic C10-C20 alkyl group and n is 1 or 2, optionally containing unsaturations in the form of double or triple bonds; (iii.) 0.001% to 10.000% by weight of at least one tri-methyltin compound of formula (CH3)3Sn(S(CH2)pCOOR3) wherein R3 is a linear, branched or cyclic C10-C20 alkyl group and p is 1 or 2, optionally containing unsaturations in the form of double or triple bonds; and (iv.) 0.001% to 15.000% by weight of at least one thioester of formula HS(CH2)qCOOR4 wherein R4 is a linear, branched or cyclic C10-C20 alkyl group and q is 1 or 2, optionally containing unsaturations in the form of double or triple bonds.