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...

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

Levy and Roll (Review of Financial Studies, 2010) have recently revived the debate related to the market portfolio's efficiency suggesting that it may be mean-variance efficient after all. This paper develops an alternative test of portfolio mean-variance efficiency based on the realistic...

The recent turmoil in the financial markets has highlighted that no asset is really free of risk. Indeed, even the supposedly safest assets, namely sovereign bonds issued by developed countries, are exposed to default risk. Despite this observation most mean-variance efficiency tests are...