This paper compares the trading patterns of amateur and professional investors during the days following the weekend. The comparison is based on all the daily transactions of a large sample of both amateurs and professionally managed investors in a major brokerage house in Israel from 1994 to 1998. We find that weekends influence both amateurs and professional investors; however they affect them in opposite directions. Individuals increase both their buy and sell activities, and their propensity to sell rises more than their propensity to buy. Professionals on the other hand tend to perform fewer buy as well as sell trades after the weekend, but unlike individuals, the drop in their activity is almost the same for buy trades and for sell trades. The results agree with previous hypotheses raised in the literature, which were not directly tested, about the effects of the weekend on the predisposition to trade of individuals and institutions in other markets. We also find that returns on the Israeli Stock Market Index are correlated in general with the behavioral patterns exhibited by the investors in our sample. In particular the returns on the days following the weekend are lower than those in other weekdays in a manner consistent with the behavioral patterns we found.

In this paper, we analyze the investment patterns of a large number of clients of a major Israeli brokerage house during 1994. We compare the behavior of clients making independent investment decisions to that of investors whose accounts were managed by brokerage professionals. Our main objective is to investigate whether the disposition effect (i.e., the tendency to sell winners quicker than losers), demonstrated in the US only for individual investors, also holds for professional investors. This analysis is important, as accepted financial theory predicts that prices are determined mainly by decisions made by professionals. We show that both professional and independent investors exhibit the disposition effect, although the effect is stronger for independent investors. The second objective of our study is the comparison of trade frequency, volume and profitability between independent and professionally managed accounts. We believe that these comparisons not only provide insights of their own, but also help to put the differences in the disposition effect in a wider perspective. We demonstrate that professionally managed accounts were more diversified and that round trips were both less correlated with the market and slightly more profitable than those of independent accounts.

We find a herding tendency among both amateur and professional investors and conclude that the propensity to herd is lower in the professionals. These results are obtained both when we consider herding into individual stocks and herding into stocks in general. Herding depends on the firm’s systematic risk and size, and the professionals are less sensitive to these variables. The differences between the amateurs and the professionals may be attributable to the latter’s superior financial training. Most of the results are consistent with the theory that herding is information-based. We also find that the herding behavior of the two groups is a persistent phenomenon, and that it is positively and significantly correlated with stock market returns’ volatility. Finally, herding, mainly by amateurs, causes market volatility in the Granger causality sense.

Itzhak Venezia, Haim Levy; Optimal Claims in Automobile Insurance, The Review of Economic Studies, Volume 47, Issue 3, 1 April 1980, Pages 539–549, https:/