The paper shows that financial market equilibria need not exist if agents possess cumulative prospect theory preferences with piecewise-power value functions. The reason is an infinite short-selling problem. But even when a short-sell constraint is added, non-existence can occur due to...

We prove a formula for the computation of optimal financial investments in an expected utility framework with arbitrary (not necessarily concave) utility functions. This extends classical results on optimal financial investments for strictly concave utility functions and is of importance...

We prove that under very weak conditions optimal financial products have to be co-monotone with the inverted state price density. Optimality is meant in the sense of the maximization of an arbitrary preference model, e.g. Expected Utility Theory or Prospect Theory. The proof is based on methods...