Herd Behavior of Returns in the Futures Exchange Market

The herd behavior of returns is investigated in Korean futures exchange market. It is obtained that the probability distribution of returns for three types of herding parameter scales as a power law $R^{-\beta}$ with the exponents $ \beta=3.6$(KTB203) and 2.9(KTB209) in two kinds of Korean treasury bond. For our case since the active state of transaction exists to decrease lesser than the herding parameter $h=2.33$, the crash regime appears to increase in the probability with high returns values. Especially, we find that it shows a crossover toward a Gaussian probability function near the time step $\Delta t=360$ from the distribution of normalized returns. Our result will be also compared with other well-known results.