Speculators often advertise arbitrage opportunities in order to persuade other investors and thus accelerate the correction of mispricing. This induces under-diversification: a risk-averse arbitrageur will optimally advertise only one of several mispriced assets, and overweigh it in his...

Most stock exchange regulators around the world reacted to the 2007-2009 crisis by imposing bans or regulatory constraints on short-selling. Short-selling restrictions were imposed and lifted at different dates in different countries, often applied to different sets of stocks and featured...