The utility maximization problem of "ratchet investors" who do not tolerate any decline in their consumption rate is solved explicitly for all felicity functions in a Markovian framework which includes Brownian motion and Poisson processes as special cases. The optimal consumption plan turns out...

We study the intertemporal utility maximization problem for Hindy-Huang-Kreps utilities. Necessary and sufficient conditions for optimality are given. An explicit solution is provided for a large class of utility functions. In particular, the case of separable power utilities with a finite time...

We extend the analysis of the intertemporal utility maximization problem for Hindy-Huang-Kreps utilities reported in Bank and Riedel (1998) to the stochastic case. Existence and uniqueness of optimal consumption plans are established under arbitrary convex portfolio constraints, including both...

We prove existence of an Arrow-Debreu equilibrium when agents' preferences exhibit local substitution in the sense of Hindy, Huang, and Kreps (1992). Efficient allocations and supporting price functionals are identified and characterized. Under Hindy Huang Kreps preferences, equilibrium price...

This paper tests the validity of Present Value (PV) models of stock prices by employing a two-step strategy for testing the null hypothesis of no cointegration against alternatives which are fractionally cointegrated. Monte Carlo simulations are conducted to evaluate the power and size...

When people decide about saving and consumption across the various periods of their life time they take into account their life expectancy when comparing present and future needs and resources for satisfying them. The experimental design, applied at two sites (Humboldt-University at Berlin and...

In a complete financial market every contingent claim can be hedged perfectly. In an incomplete market it is possible to stay on the safe side by superhedging. But such strategies may require a large amount of initial capital. Here we study the question what an investor can do who is unwilling...

An investor faced with a contingent claim may eliminate risk by (super-)hedging in a financial market. As this is often quite expensive, we study partial hedges, which require less capital and reduce the risk. In a previous paper we determined quantile hedges which succeed with maximal...