Unconventional Monetary Policy and the Behavior of Shorts.

We investigate the behavior of shorts, considered sophisticated investors, before and after a set of Federal Reserve unconventional monetary policy announcements that spot bond markets did not fully anticipate. Short interest in agency securities systematically predicts bond price changes and other asset returns on the days of monetary announcements, particularly when growth or monetary news is released, indicating shorts correctly anticipate these surprises. Shorts also systematically rebalance after announcements in the direction of the announcement surprise when the announcement releases monetary or growth news, suggesting that shorts interpret these announcements to imply further yield changes in the same direction. [ABSTRACT FROM AUTHOR]