[1, 2] have shown for the dynamic spectrum allocation problem that a competitive market model (which sets a price for transmission power on each channel) leads to a greater social utility (by reducing cross talk) than the Nash equilibrium. We show that the market equilibrium is the solution of a linear complementarily problem, and hence the market model possesses no additional computational complexity beyond that of the Nash equilibrium model and can be calculated efficiently. We also show that under reasonable conditions, any t^atonnement process for adjusting the prices will converge to the equilibrium prices. The conditions are that users of a channel experience the same noise levels and that the cross-talk effects between users are low-rank and weak.