Exploiting cross-sectional and time-series variations in European regulations during the July 2008–June 2009 period, we show that: (1) prohibition on covered short selling raises bid-ask spread and reduces trading volume, (2) prohibition on naked short selling raises both volatility and...

In the aftermath of the financial crisis, market efficiency is being heavily criticized. However, the volatility-based criticisms rely on false grounds as efficiency and speculative bubbles are compatible. Indeed, the efficient market model is about rationality and information, not about...

Criticizing the Efficient Market Hypothesis (EMH) on the basis of highly volatile asset prices is conceptually wrong as efficiency is about rationality and information, not about stability. Speculative bubbles are compatible with rational valuation, and hence with market efficiency. As rational...

When a financial crisis breaks out, speculators typically get the blame whereas fundamentalists are presented as the safeguard against excessive volatility. This paper proposes an asset pricing model where two types of rational traders coexist: short-term speculators and long-term...

When a financial crisis breaks out, speculators typically get the blame whereas fundamentalists are presented as the safeguard against excessive volatility. This paper proposes an asset pricing model where two types of rational traders coexist: short-term speculators and long-term...