Tbe Review of Financial Studies/v4n21991 uninformed trader, S(i)P,+ B(i), is normally distributed. Therefore one can use the assumption that their utility functions are negative exponential and rewrite their objective in a mean-variance frame vork as maxv=S()E(P|P)+B()-0.50s()var(f|P),(8) subject to the budget constraint [S()-S0()P+[B()-B()=0. The first-order condition of (8), subject to(9), is then used to deter mine the individual demand schedule of each uninformed investor The demand, it should be noted is the same for all the uninformed 2.3 Feasible aggregate demand curves Aggregating all the individual demands we get S()f( nE(P I P)-PI 8 Var(P I P) (10) Substituting for E(P I P)from(6) and for Var(P I P) from(7) in(10), we obtain a differential equation in S(P) K t k2st KSPt KS'st KsS=0 (11) where K1=S,K2=-1 G2-0282o2 K={1+1+K3+k32}≥ K5=-(2K3+6o2) The solution of(11) gives us all the possible aggregate demand curves that satisfy the first-order condition of the informed investor Her second-order condition [obtained by differentiating (3) with respect to P] further restricts this set, and provides the complete set of feasible aggregate demand curves. In order to find the set of equi libria, we analyze the problem in three steps. First, Proposition 1 establishes the set of solutions satisfying Equation(11). Second, Prop osition 2 uses the second-order condition to find restrictions that any 262