We are interested in the problem of finding an optimal strategy
for a non-attainable contingent claim in an incomplete market
consisting of two traded assets. We discuss and compare the
Kunita-Watanabe and Fo¨llmer-Schweizer martingale decomposition and use them for finding the risk-minimizing trading strategy. The theory of stable spaces and minimal martingale measure is used and the differences in the models are
discussed.
