Price Clustering and Investor Sentiment

Among the anomalous findings in the finance literature, perhaps the most persistent is the finding that security prices tend to cluster on round pricing increments. The author examines how investor sentiment influences the degree of price clustering. Both univariate and multivariate tests show a contemporaneous correlation between price clustering and investor sentiment. Recognizing the need to make stronger causal inferences, the author conducts 2 additional sets of tests. First, the author uses the technology bubble period as natural experiment and examine the price clustering of technology vis-à-vis nontechnology stocks. Results show that price clustering is markedly higher in tech stocks than in nontech stocks during this period of rising, sector-specific, investor sentiment. Second, the author estimates a vector autoregression process and examines the impulse responses of price clustering to exogenous shocks in investor sentiment. The results from these tests indicate that causation flows from sentiment to clustering instead of the other way around.