Characterizing bid-ask prices in the Brazilian equity market

This paper presents evidence of long-range dependence in bid-ask prices for individual equity prices in the Brazilian stock market. Moreover, using the Hurst exponent calculated by the Local Whittle method as a measure of long-range dependence, we find evidence supporting that bid-ask prices shows a stronger long-range dependence than the one usually found in closing and opening prices. Finally, we show that bid-ask prices may be characterized by a distribution that decays as a power law reinforcing the results of Plerou et al. [Quantifying fluctuations in market liquidity: analysis of the bid-ask spread, Phys. Rev. E 71 (2005) 046131]. (c) 2006 Elsevier B.V. All rights reserved.