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...

We study the effect of transaction costs (e.g., a trading fee or a transaction tax, like the Tobin tax) on the aggregation of private information in financial markets. We analyze a financial market à la Glosten and Milgrom, in which informed and uninformed traders trade in sequence with a...

We study the informational channel of financial contagion in the laboratory. In our experiment, two markets with correlated fundamentals open sequentially. In both markets, subjects receive private information. Subjects in the market opening second also observe the history of trades and prices...