This research examines capital income taxation for a prospect theory investor under some acceptable in the literature reference levels relative to which are the changes in the level of wealth valued. Depending on the reference level, some results indicate that it is possible for a capital income tax increase not to stimulate risk taking even if the tax code provides attractive full loss offset provisions. However, risk taking can be stimulated when investors compare their reference level with others. Risk taking can increase also if the investor interprets part of the tax as a loss instead as a reduced gain. Then the investor becomes risk seeking and moves away from the discomfort zone of relative losses. This later response to taxation causes private risk taking to increase.