We develop a new methodology to estimate the importance of herd behavior in financial markets: we build a structural model of informational herding that can be estimated with financial transaction data. In the model, rational herding arises because of information-event uncertainty. We estimate the model using data on a NYSE stock (Ashland Inc.) during 1995. Herding often arises and is particularly pervasive on some days. The proportion of herd buyers (sellers) is 2 percent (4 percent) and is greater than 10 percent in 7 percent (11 percent) of information-event days. Herding causes important informational inefficiencies, amounting, on average, to 4 percent of the expected asset value.

We study herd behavior in a laboratory financial market with financial market professionals. We compare two treatments, one in which the price adjusts to the order flow so that herding should never occur, and one in which event uncertainty makes herding possible. In the first treatment, subjects herd seldom, in accordance with both the theory and previous experimental evidence on student subjects. A proportion of subjects, however, engage in contrarianism, something not accounted for by the theory. In the second treatment, the proportion of herding decisions increases, but not as much as theory suggests; moreover, contrarianism disappears altogether.

We study herd behavior in a laboratory financial market with financial market professionals. We compare two treatments, one in which the price adjusts to the order flow so that herding should never occur, and one in which event uncertainty makes herding possible. In the first treatment, subjects herd seldom, in accordance with both the theory and previous experimental evidence on student subjects. A proportion of subjects, however, engage in contrarianism, something not accounted for by the theory. In the second treatment, the proportion of herding decisions increases, but not as much as theory suggests; moreover, contrarianism disappears altogether.

This special edition of Contemporary Studies in Economic and Financial Analysis offers seventeen chapters from invited participants in the International Applied Social Science Congress, held in Turkey between the 19th and 21st April 2018.

Policymakers often express concern that herding by financial market participants destabilizes markets and increases the fragility of the financial system. This paper provides an overview of the recent theoretical and empirical research on herd behavior in financial markets. It addresses the following questions: What precisely do we mean by herding? What could be the causes of herd behavior? What success have existing studies had in identifying such behavior? And what effect does herding have on financial markets?

Hedge funds are collective investment vehicles, often organized as private partnerships and resident offshore for tax and regulatory purposes. Their legal status places few restrictions on their portfolios and transactions, leaving their managers free to use short sales, derivative securities, and leverage to raise returns and cushion risk. This paper considers the role of hedge funds in financial market dynamics, with particular reference to the Asian crisis.