A flexible compound comprising PVC or its co-polymers; greater than 10 to 200 parts by weight of at least one bio-based primary plasticizer comprising epoxidized fatty acid esters, wherein the fatty acids are derived from natural oils and animal fats, based on 100 parts by weight of PVC or its co-polymers; and 0.001 to 10 parts by weight of a mixed metal stabilizer comprising a zinc compound and at least one metal compound where the metal is selected from Li, Na, K, Mg, Ca, Sr, Ba, Cd, Al, La, Ce or rare earth metals, based on 100 parts by weight of PVC or its co-polymers, wherein an atomic ratio of metal/Zn for the mixed metal stabilizer is less than 1.0.