The effect of corporate disclosure in emerging markets is not clearly predictable because of the prevalent information leakage prior to disclosure. We empirically examine the effectiveness of Regulation Fair Disclosure (Reg FD) in reducing information asymmetry among equity traders in an emerging market. Specifically, we test whether fair disclosure activity is negatively related to the probability of informed trading (PIN). Multivariate tests on a sample of listed companies in Korea subject to Reg FD reveal the following: (1) more frequent disclosure under Reg FD is related to lower information asymmetry, and (2) this relation differs across the types of disclosure, with the effect of qualitative disclosures on the PIN being weaker than that of quantitative disclosures. Evidence also indicates that the negative association between fair disclosure activities and information asymmetry is more (less) pronounced for firms with poorer (better) information environments where selective information leakage is more (less) likely. The results are robust to sensitivity tests. Our findings have implications for disclosure regulations in emerging markets, given that the existing literature casts doubt on the effectiveness of corporate disclosure in such markets.