Hydrolytically stable phosphites as secondary antioxidants for polymer resins comprising a phosphite and an amine compound. The phosphite may be a liquid phosphite composition. The amine compound may have the structure of formula I: wherein x is 1, 2 or 3; R1 is selected from the group consisting of hydrogen, and straight or branched C1-C6 alkyl, and R2 is selected from the group consisting of straight or branched C1-C30 alkyl.