A Counterexample Concerning the Variance-Optimal Martingale Measure
Document type:
Zeitschriftenaufsatz
Author(s):
Cerny, A.; Kallsen, J.
Non-TUM Co-author(s):
ja
Cooperation:
international
Abstract:
The present note addresses an open question concerning a sufficient characterization of the variance-optimal martingale measure. Denote by S the discounted price process of an asset and suppose that Q* is an equivalent martingale measure whose density is a multiple of 1 - φ · S(T) for some S-integrable process φ. We show that Q* does not necessarily coincide with the variance-optimal martingale measure, not even if φ · S is a uniformly integrable Q*-martingale.