Homotheticity induces a dramatic statistical bias in the estimates of the intratemporal and intertemporal substitutions. I find potent support in favor of nonhomotheticity in aggregate consumption data, with nondurable goods being necessities and durable goods luxuries. I obtain the...

We analytically show that a common across rich/poor individuals Stone-Geary utility function with subsistence consumption in the context of a simple two-asset portfolio-choice model is capable of qualitatively and quantitatively explaining: (i) the higher saving rates of the rich, (ii) the...