Conventional discounted cash flow techniques fail to capture the risk associated with investments. This paper proposes an annual cash flow model that considers risk, cost structure and inventory liquidation in the evaluation of investment alternatives. The risk differential of investments is included using the capital asset pricing model while the stochastic version of the cost-volume-profit approach is used to consider inventory liquidation and cost structure. Tradeoffs between fixed and variable costs have been investigated, and portrayed using iso-cash flow curves. The proposed cash flow model has been developed, in particular, to enable an accurate evaluation of advanced manufacturing systems.