Turn-of-the-month and intramonth effects: Explanation from the important macroeconomic news announcements

This study provides a new and economically plausible explanation for turn‐of‐the‐month and intramonth anomalies. It is suggested that these anomalies arise from clustered information, namely from important macroeconomic news announcements, which are released systematically at a certain point each month. It is verified that both anomalies exist in SP100 returns. However, once the effect of macroeconomic news announcements has been taken into account, these anomalies disappear. A measure is proposed which uses information from option‐implied volatilities to account for the changes in expected risk premium caused by news announcements. This measure is found to capture incompletely the effects of news announcements, which may due to the misreactions observed on the options market or alternative explanations, such as increased liquidity or investors' overreaction resulting in higher realized returns. Consequently, the underlying mechanism remains to some extent inconclusive although the empirical results provide strong support for the macroeconomic news announcement hypothesis. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27:105–126, 2007