Anecdotal data affirms that companies applying Lean Six Sigma in their operations not only deliver higher quality products and services, but also obtain superior financial results. The goal of this research was to empirically verify anecdotal data. The study proposed to analyze a group of publicly traded manufacturing companies with the intent of verifying if a correlation exists between companies being lean and the attainment of superior returns on investments. The researcher performed a series of statistical tests comparing key Financial Performance Indicators (FPI) extracted from annual reports (10-K) from a large pool of companies. The outcome of this study showed that superior financial rewards result from a systematic application of lean and quality tools. At the conclusion of this thesis we verified that companies having a business model that stimulates a high level of communication between them and their markets - because they are lean - obtained substantially higher financial advantages when compared to companies that still followed a more traditional mode of production. The results also revealed that lean companies obtained on average Return on Invested Capital (ROIC) 10% higher than mass producers. Therefore, companies wanting to strategically invest their capital should consider Lean Six Sigma as a source of competitive advantage. Another strategic insight derived from this study was the recognition of signs of a smart business. Potential investors should look for the presence of lean and quality improvement programs as one sign that capital is being wisely invested to generate value. Another sign is how well historically ROIC have performed against Weighted Average Cost of Capital (WACC). The research revealed that, on average, lean companies had ROIC of 16%. Assuming that the hurdle rate (WACC) for most companies is near 10%, having ROIC of 16% is an incentive to become lean, thus allowing such companies to create value for their shareholders. Finally, we learned that many factors affect ROIC, namely, brand equity, market positioning, patents, core competency, innovation, leadership, etc. However, the presence of a Lean Six Sigma program in a manufacturing business was a strong positive factor impacting ROIC.