Results: Time-Stability of Portfolio Returns

Abstract

In the last chapter, we identified a systematically positive relationship between abnormal volume and expected returns in the cross-section of Swiss stocks. In a next step, we investigate the robustness of portfolio returns across time and different market regimes, which is our research question [2]. This set of analyses commences the testing of the practicability of abnormal volume based portfolio strategies, which continues in chapter 6 (investigation of the economic significance of portfolio returns). The focus of this chapter is abnormal volume, because it is the only measure investigated shown to systematically and significantly relate to the cross-section of Swiss stock returns. However, we also briefly analyze the time-stability of the other volume measures, namely volume level, volume growth, and variability in volume. The reason is that there exists the possibility that these other volume-return relations are only systematically significant in specific states of the market, which would be an interesting finding by itself. The methodology applied is described in detail above, 3.3.2. Nevertheless, we repeat the most important aspects as deemed necessary.