A new empirical reduced-form model for credit rating transitions is introduced. It is a parametric intensity-based duration model with multiple states and driven by exogenous covariates and latent dynamic factors. The model has a generalized semi-Markov structure designed to accommodate many of...

An intensive and still growing body of research focuses on estimating a portfolio’s Value-at-Risk.Depending on both the degree of non-linearity of the instruments comprised in the portfolio and thewillingness to make restrictive assumptions on the underlying statistical distributions, a...

We solve for the optimal portfolio allocation in a setting where both conditional correlation and theclustering of extreme events are considered. We demonstrate that there is a substantial welfare loss indisregarding tail dependence, even when dynamic conditional correlation has been accounted...

Several Bayesian model combination schemes, including some novel approaches that simultaneously allow for parameter uncertainty, model uncertainty and robust time varying model weights, are compared in terms of forecast accuracy and economic gains using financial and macroeconomic time series....

This paper uses the market-standard Gaussian copula model to show that fair spreads on CDO tranches are much higher than fair spreads on similarly-rated corporate bonds. It implies that credit ratings are not sufficient for pricing, which is surprising given their central role in structured...

We propose a simple network–based methodology for ranking systemically important financial institutions. We view the risks of firms –including both the financial sector and the real economy– as a network with nodes representing the volatility shocks. The metric for the connections of the...

CoCo’s (contingent convertible capital) are designed to convert from debt to equity when banks need it most. Using a Diamond-Dybvig model cast in a global games framework, we show that while the CoCo conversion of the issuing bank may bring the bank back into compliance with capital...

Most stock exchange regulators around the world reacted to the 2007-2009 crisis byimposing bans or regulatory constraints on short-selling. Short-selling restrictions wereimposed and lifted at different dates in different countries, often applied to different sets ofstocks and featured different...

Countless test statistics can be written as quadratic forms in certain random vectors, or ratios thereof. Consequently, their distribution has received considerable attention in the literature. Except for a few special cases, no closed-form expression for the cdf exists, and one resorts to...

The Basel II Accord requires that banks and other Authorized Deposit-taking Institutions (ADIs) communicate their daily risk forecasts to the appropriate monetary authorities at the beginning of each trading day, using one or more risk models to measure Value-at-Risk (VaR). The risk estimates of...