Finally, for completeness we should note that later work (Harvard Discussion Paper No. 234, 1971) has shown that when investors' risk-aversions are functionally related to their ending wealth, the investor's personal equilibrium depends upon a combination of his risk-aversion and its first derivative, but the market price of risk aggregates the investor's more complex marginal rates of substitution of return and risk in exactly the same way as it aggregates investors risk-aversions per se in simple situations. iMoreover, all the statements made above on the basis of aggregations of risk-aversions are shown to be valid in the more complex analysis.