This paper studies the effect of hedge-fund trading on idiosyncratic risk. We hypothesize that while hedge-fund activity would often reduce idiosyncratic risk, high initial levels of idiosyncratic risk might be further amplified due to fund loss limits. Panel-regression analyses provide...

This paper documents that options held from one expiration date to the next achieve significantly lower returns when there are four versus five weeks between expiration dates. The average return differential ranges from 12 basis points per week for delta-hedged put portfolios to 89 basis points...