  This paper concerns the dual risk model, dual to the risk model for insurance
applications, where premiums are surplus-dependent. In such a model premiums
are regarded as costs, while claims refer to profits. We calculate the mean of
the cumulative discounted dividends paid until ruin, if the barrier strategy is
applied. We formulate associated Hamilton-Jacobi-Bellman equation and identify
sufficient conditions for a barrier strategy to be optimal. Some numerical
examples are provided when profits have exponential law.
