the like such as triphenyl phosphites tris alkylated phenol phosphites tris mono di and trialkyl phenol phosphites tris alkyl phosphites alkyl diphenyl phosphites and the like as well as the bis alkyl and aryl esters of pentaerythritol diphosphites and oligomeric and polymeric phosphite esters of diphenolic and bis phenolic compounds commercially available examples of such phosphite ester compounds include triphenyl phosphite tris nonylphenyl phosphite diphenyl dodecyl phosphite tris dodecyl phosphite tri di t butylphenyl phosphite distearyl pentaerythritol diphosphite bis di t butylphenyl pentaerythritol diphosphite the oligomeric alkyl phosphites of bis phenol a and the like also useful are mixtures of two or more of such phosphite ester compounds such compounds have long been known for use as stabilizers in pvc and are widely available from commercial sources the zinc compounds useful in the practice of this invention are zinc salts of carboxylic acids and more particularly are zinc salts of fatty acids such as zinc stearate and the like the stabilizer composition of this invention will consist of from 24 to 45 wt alkyl tin mercaptide from 45 to 70 wt phosphite and from 6 to 11 wt zinc salt the composition will generally be employed in amounts of about 1 to about 5 parts by weight per hundred parts by weight phr of pvc resin and preferably at a level which will provide from about 0 5 to about 2 0 phr of alkyl.