Herding behaviour and sentiment: Evidence in a small European market 

Abstract

This work studies herding behaviour in a small European market, by analysing the stocks that constitutedthe Portuguese stock PSI-20 index, for the period between 2003 and 2011. The two different approachesused to measure herding intensity led to different results, suggesting that measurements of the herdingphenomenon are sensitive to the method used. Consequently, there is a need for further research into themethodology used to test this phenomenon. Additionally, the study analyses the relationship betweenherd behaviour and investor sentiment, an area that has been little explored. In applying causality teststo the impact of sentiment on herd behaviour, only weak evidence is found that sentiment influencesherding.

The short of it: Investor sentiment and anomalies

Abstract
This study explores the role of investor sentiment in a broad set of anomalies in cross-sectional stock returns. We consider a setting in which the presence of market-wide sentiment is combined with the argument that overpricing should be more prevalent than underpricing, due to short-sale impediments. Long-short strategies that exploit the anomalies exhibit profits consistent with this setting. First, each anomaly is stronger (its long-short strategy is more profitable) following high levels of sentiment. Second, the short leg of each strategy is more profitable following high sentiment. Finally, sentiment exhibits no relation to returns on the long legs of the strategies.