Diversification benefits depend on the correlation between assets. Unfortunately, asset correlation increases when it is most needed. We examine bond correlation using a broad sample of US corporate bonds. We find bond correlation to be higher during the financial crisis in 2008. Increased bond...

In this paper we develop the first estimator of the covariance matrix that relies solely on forward-looking information. This estimator only uses price information from a cross-section of plain-vanilla options. In an out-of-sample study for US blue-chip stocks we show that a minimum-variance...