A semi-strong efficient market incorporates relevant new information immediately. Using an event study, we investigate whether and to what extent regular earnings announcements of Swiss companies listed on the Swiss Market Index show the expected effects in share prices. For this purpose, we test for abnormal returns caused by earnings announcements in the period from 2012 until 2022. In contrast to previous studies of the Swiss market, we find that deviations from analysts’ expected earnings lead to pronounced immediate movements in stock prices, as predicted by the semi-strong efficient market hypothesis. Pre- and post-announcement abnormal returns are modest and generally not statistically significant.