We introduce the concept of “negative bubbles” as the mirror image of standard financial bubbles, in which positive feedback mechanisms may lead to transient accelerating price falls. To model these negative bubbles, we adapt the Johansen-Ledoit-Sornette (JLS) model of rational expectation...

We study bailouts of banks that suffer from debt overhang problems and have private information about the quality of their assets-in-place and new investment opportunities. Menus of bailout plans are used as a screening device. Constrained-optimality involves over capitalization and nonlinear...

We present an extension of the Johansen-Ledoit-Sornette (JLS) model to include an additional pricing factor called the Zipf factorʺ, which describes the diversification risk of the stock market portfolio. Keeping all the dynamical characteristics of a bubble described in the JLS model, the new...

The Johansen-Ledoit-Sornette (JLS) model of rational expectation bubbles with finite-time singular crash hazard rates has been developed to describe the dynamics of financial bubbles and crashes. It has been applied successfully to a large variety of financial bubbles in many different markets....

This paper seeks to inform about a feature of monetary policy that is largely overlooked, yet occupies a central role in modern monetary and financial systems, namely central bank collateral frameworks. Their importance can be understood by the observation that the money at the core of these...

The spread between unsecured and repo rates (collateral spread) fluctuates substantially and is negative on a significant portion of days. Recent theoretical work argues that collateral spreads are determined by a constrained-arbitrage relation between the unsecured rate, the repo rates, and the...

Repo rates frequently exceed unsecured rates in practice. As an explanation, this paper derives a constrained-arbitrage relation between the unsecured rate, the repo rate, and the illiquidity adjusted expected rate of return of the underlying collateral. The theory is based on unsecured...