This paper examines the role of investor learning in facilitating price dis- covery following important macroeconomic announcements. Leveraging a unique feature of unscheduled macroeconomic news releasing outside of regular trading hours of Chinese stock markets, we investigate the impact of investor learning, in the absence of trading, on the price discovery process. We show that investors’ overnight learning activities on social media during the non-trading period – from the release of macro news to the market opening time – significantly enhance the price discovery once trading resumes. This overnight learning helps level the information playing field among heterogeneous investors, leading to reduced information asymmetry at market opening.