There has been a long debate about whether speculators are stabilizing or not.We consider a model where speculators have a stabilizing role in normal times,but may also provoke large risk panics. The very feature that makes arbitrageursliquidity providers in normal times, namely their tolerance...

We present and compare two dierent approaches to conditional riskmeasures. One approach draws from convex analysis in vector spaces andpresents risk measures as functions on Lp spaces, while the other approachutilizes module-based convex analysis where conditional risk measures aredened on Lp...

It is well known that mean-variance portfolio selection is a time-inconsistent optimalcontrol problem in the sense that it does not satisfy Bellman’s optimalityprinciple and therefore the usual dynamic programming approach fails. We developa time-consistent formulation of this problem, which...