At the end of January 2021, a group of stocks listed on US stock exchanges experienced sudden surges in their stock prices, which - coupled with high short interest – led to brief short squeeze episodes. We argue that these short squeezes were the result of coordinated trading by retail...

On October 26, 2008, Porsche announced a largely unexpected domination plan for Volkswagen. The resulting short squeeze in Volkswagen's stock briefly made it the most valuable listed company in the world. We argue that this was a manipulation designed to save Porsche from insolvency and the...

There has been a long debate about whether speculators are stabilizing or not. We consider a model where speculators have a stabilizing role in normal times, but may also provoke large risk panics. The very feature that makes arbitrageurs liquidity providers in normal times, namely their...

We quantify the effects of financial regulation in a general equilibrium model with market microstructure. Fund managers trade stocks and bonds in an order-driven market, subject to transaction taxes and constraints on short-selling and leverage. Results are obtained on the equilibrium...

Whether proprietary traders provide or take liquidity, and how their behavior evolves over the business cycle and across stocks, remains at the center of an ongoing debate. Using a unique dataset from the NYSE, we document that proprietary traders concentrate their trades in large and liquid...

Return anomalies are most pronounced among distressed stocks. We attribute this finding to the role of misvaluation and investors' inability to value distressed stocks correctly. We treat distressed stocks as options and construct a valuation model that explicitly takes into account the value of...

We develop statistical methods to detect informed trading in options markets. We apply these methods to 31 companies from various sectors over 14 years analyzing approximately 9.6 million option prices. We find that option informed trading tends to cluster prior to certain events, takes place...

This appendix extends the empirical results in Chesney, Crameri, and Mancini (2011). Informed trading activities on put and call options are analyzed for 19 companies in the banking and insurance sectors from January 1996 to September 2009. Our empirical findings suggest that certain events such...

Prediction (or information) markets are markets where participants trade contracts whose payoff depends on unknown future events. Studying prediction markets allows to avoid many problems, which arise in some artificially designed behavioral experiments investigating collective decision making...

We conduct an experiment assessing the extent to which people trade off the economic costs of truthfulness against the intrinsic costs of lying. The results allow us to reject a type-based model. People's preferences for truthfulness do not identify them as only either quot;economic typesquot;...