This paper suggests that earnings announcements provide information that allows certain traders to make judgements about a firm's performance that are superior to the judgements of other traders. As a result, there may be more information asymmetry at the time of an announcement than in nonannouncement periods. More information asymmetry implies that bid–ask spreads increase, suggesting that market liquidity decreases at the time of an earnings announcement. Furthermore, informed opinions resulting from public disclosure may lead to an increase in trading volume, despite the reduction in liquidity that accompanies announcements.