We examine the effect of information asymmetry on equity prices in the local A- and foreign B-share market in China. We construct measures of information asymmetry based on market microstructure models, and find that they explain a significant portion of cross-sectional variation in B-share discounts, even after controlling for other factors. On a univariate basis, the price impact measure and the adverse selection component of the bid-ask spread in the A- and B-share markets explains 44% and 46% of the variation in B-share discounts. On a multivariate basis, both measures are far more statistically significant than any of the control variables. © 2008 by The American Finance Association.