Portfolio Performance in Relation to Herding Behavior in the Taiwan Stock Market

Herding behavior, which is investing in crowded stocks during a specific period, will push the target stocks' return down or up. Using both institutional and individual investors' intraday trading data to calculate the measure of daily herding, we find that a zero-cost investing strategy of buying long and high and selling short and high is profitable. The profits gained strategically through herding by individual investors are greater than those earned by institutional investors. This means institutional investors reflect the information quickly and, although they do behave as a herd, it is harder to exploit the herding of institutional investors to make strategically gained profits.