He also partially names a theorem that demonstrated that under certain assumptions, the value of a firm is not affected by whether it is financed by equity or debt.  
This economist developed a theory suggesting that bond investors have a preference for a maturity length that can only be overturned if there is a risk premium, called "preferred habitat theory." Along with Duesenberry he names a consumption function that postulates that current consumption is determined not just by current income, but also by its previous highest peak.  He designed a large scale model of the US economy for the Federal Reserve, the MPS.  He also partially names a theorem that demonstrated that under certain assumptions, the value of a firm is not affected by whether it is financed by equity or debt.  With Robert Brumberg, he postulated that young and old households have a higher propensity to consume while middle aged households have a higher propensity to save, the "Life Cycle Hypothesis of Saving."  For 10 points, name this 1985 Nobel winner, who formulated a capital structure theorem with Merton Miller.
This economist developed a theory suggesting that bond investors have a preference for a maturity length that can only be overturned if there is a risk premium, called "preferred habitat theory."
Franco {Modigliani}