Before revision:  If P^{-1}dP/dt (the relative price change in an interval dt) is given by a suitable function of  excess demand, \mathcal{D \left( \% -S}\right) /S -1 (where D and S are demand and supply), then the distribution has tail behavior F\left( x\right) \sim x^{-\zeta} for a power \zeta that depends on the function G in P^{-1}dP/dt=G\left( D/S\right) .
After revision:  If P^{-1}dP/dt (the relative price change in an interval dt) is given by a suitable function of relative excess demand, \mathcal{D \left( \% -S}\right) /S -1 (where D and S are demand and supply), then the distribution has tail behavior F\left( x\right) \sim x^{-\zeta} for a power \zeta that depends on the function G in P^{-1}dP/dt=G\left( D/S\right) .