Recent research has highlighted the puzzling phenomenon of overnight stock returns vastly outperforming day returns. The anomaly has been fairly well documented but the underlying factors are still debated. This paper explores earnings announcements on the Nasdaq Stockholm stock exchange and the announcements effects on the overnight returns for individual stocks. Data from the stock price index OMXSPI and the OMXS30 constituents provide the empirical basis for our research. We hypothesize that earnings announcements have a positive contribution to overnight returns for individual stocks. Our quantitative regression study supports the hypothesis that the overnight returns are particularly strong during days when earnings reports are announced. These encouraging results provide motivation for extending the research to other markets where the phenomenon has been observed.