Abstract: A catalyst composition suitable for reacting hydrocarbons, e.g., conversion processes such as fluidized catalytic cracking (FCC) of hydrocarbons, comprises attrition resistant particulate having a high level (30-85%) of stabilized zeolites having a constraint index of 1 to 12. The stabilized zeolite is bound by a phosphorous compound, alumina and optional binders wherein the alumina added to make the catalyst is about 10% by weight or less and the molar ratio of phosphorous (P2O5) to total alumina is sufficient to obtain an attrition index of about 20 or less. The composition can be used as a catalyst per se or as additive catalyst to a conventional catalyst and is especially suitable for enhancing yields of light olefins, and particularly ethylene, produced during conversion processes.