This study has as it principal objective to verify the contribution of advertising expenditures to firm value. To reach this goal, a dynamic and stochastic model was developed. The dynamic effect captures the advertising expenditure impact on the cash flows in subsequent periods. The stochastic effect reflects the uncertainty caused by business cycles that influence the decision as to the amount to be spent. Finally, with optimization it is possible to compare whether the cash flow generated, under these specific effects, is, in fact, higher. The results indicate evidence that advertising expenditures, when effectively spent, can contribute to firm value. Data of American companies of the consumer discretionary sector from 1998 to 2007 were employed to test empirically the proposed model. It is also important to point out the interface between marketing and finance through the multidisciplinary character of this research.