Individuals contemplate a number of factors in making decisions, including their tolerance of risk, their emphasis on maximizing gains, and their perception of current and future resources. I have proposed that depressed individuals utilize a scarcity and depletion 'portfolio theory,' such that they place less emphasis on maximizing gains, see themselves as having fewer resources (currently and in the future), and view outcomes as unpredictable and uncontrollable. Depressed individuals suffer losses more and enjoy gains less, stop-out early, have a low threshold for defining loss and a high threshold for defining gain, and are risk-averse. This 'portfolio theory' is extended to a model of manic decision making. Individuals in a manic phase are viewed as operating with 'market assumptions' of abundance and magnification, rather than scarcity and depletion. Specifically, manic individuals are described here as 'risk-lovers' who view themselves as having unlimited current and future resources, believe they have close to infallible prediction and control of outcomes, place high hedonic utility on gains, and have low dis-utility for losses. In addition, their resistance to helplessness is attributed to their low stop-loss criterion, their high threshold for defining loss and low threshold for defining gain, and their discounting of regret. Theoretical, empirical and clinical implications are developed from this conceptualization.