مهدی کریمی

Herding behavior is typically described as the inclination of investors to follow the actions of others in their investment decisions. Herding represents a behavioral tendency in which investors rely on collective rather than private information. Herd literature shows that return jumps can serve as a representation of information arrival, leading to significant price changes. This proposition is introduced due to its potential impact on investor sentiment, assuming greater awareness among other investors as a factor related to the occurrence of herding. Furthermore, it is believed that, in conditions of negative market returns, market participants are more inclined to mimic the behavior of others due to the stress induced by the risk incurred. In the background of previous research, evidence indicates the occurrence of herd behavior on days with return jumps and negative returns. In this study, we investigated herding behavior and its asymmetry through the utilization of return jumps, employing the CSAD method. Under circumstances in which there were no occurrences of return jumps and without taking into account negative market returns, our research was unable to verify the existence of herding at the market level. Nevertheless, when return jumps and negative market returns were present, the occurrence of herd behavior was proven, and the asymmetry of herd behavior was also verified.

Herd behavior, the tendency of individuals to mimic the actions of a larger group, significantly impacts capital markets by influencing stock prices, market liquidity, and overall market stability. This phenomenon has garnered significant attention in financial studies due to its implications for both institutional and individual investors, contributing to increased market volatility and potential crashes. Various methodologies have been developed to assess herd behavior, revealing its presence across diverse market conditions, including periods of high distress and volatility. This study examines macro herding in the Tehran Stock Exchange from March 2016 to February 2024, using weekly asset returns to measure herd behavior among listed companies. For the first time in Iran, we employ the TV method to calculate herding. The TV method offers two primary advantages: it is adept at identifying macro herding because it captures the collective trading direction of investors, and it operates independently of asset pricing models, minimizing biases associated with those models. Focusing on the collective trading direction, we aim to detect significant deviations in stock price movements indicative of herd behavior. Our findings indicate that herd behavior is more pronounced during extreme market conditions, both positive and negative, with a particularly notable increase during periods of negative market returns. This study provides insights into the dynamics of investor behavior in the Tehran Stock Exchange, highlighting the importance of monitoring such behavior to mitigate its potential adverse effects on market stability.

The environment of seas has undergone geopolitical changes in recent decades, which has had a profound impact upon the nature of seapower. The aim of the current research is to expound on the new nature of seapower in the 21st century. It also takes an approach that is not limited to wartime and, given the postmodern era, encompasses peace and international rivalry, especially global trade. First, the concept of classic seapower is discussed in this paper and then using the meta-analysis method, the concept of seapower in the present century is discussed by adopting a new approach. Research findings indicate that the new nature of seapower is based on the military and non-military dimensions of seapower, the relative nature of seapower, the various roles of naval forces, the new naval threats, the diverse functions of the sea environment, the context of the international order, the strategic link between seapower and land power, air and space powers, and the humanitarian operations in the sea environment. In the early years of the 21st century, these considerations have persuaded states out of taking a purely national approach to seapower and sea policy-making, but to accept multilateral interactions and cooperation by taking a transnational approach.