Financial institutions rely heavily on Value-at-Risk (VaR) as a risk measure, even though it is not globally subadditive. First, we theoretically show that the VaR portfolio measure is subadditive in the relevant tail region if asset returns are multivariate regularly varying, thus allowing for...

Jon Danielsson discusses the use of capital ratios and macroprudential regulation and describes the limitations of each policy: How banks can inflate capital ratios, how capital requirements fail to reduce the risk of aggregate shocks and how Basel III regulations burden smaller banks relative...