What moves the market? Individual firms’ earnings announcements versus macro releases as drivers of index returns

In this paper, we characterize the relative importance of two sources of fundamental market-wide news—large firms’ earnings announcements and macroeconomic releases. Our investigation is motivated by growing concerns in the financial community about the increasing impact of individual firms’ news on the broad stock market indices and the disconnect between the stock market and the economy at large. We leverage the S&P500 index futures data and use narrow intraday and overnight windows to isolate the market-wide reactions to earnings and macro announcements. We find that earnings announcements represent an economically significant source of index-level market activity—an average earnings announcement experiences around 21% (47%) of abnormal volatility (trading volume) associated with an average macroeconomic release. The returns earned over earnings announcement windows serve as a significant driver of daily index price movement. Importantly, earnings announcements’ contribution to index-level volatility has been relatively stable over our sample period from 2004 to 2018, while we observe a drastic decrease in the volatility explained by macro announcements. The latter is consistent with a growing disconnect between the stock market and the broader macroeconomy