This case study article analyzes the financial sustainability of the main Brazilian oil company in relation to a group of five other international organizations, all vertically integrated. The companies object of the study were Petrobras, ExxonMobil, Shell, BP, Chevron and Total. To that end, we carried out a careful financial analysis based on observations made in published annual reports, especially in the SEC, the Securities and Exchange Commission. The indicators were (i) operational performance; (ii) liquidity; (iii) capital structure; and (iv) profitability. Although the sample comprises similar companies, we observed that the levels of performance and consequent economic and financial sustainability differ between them. The theory of modern organization is based on three pillars: corporate finance theory, corporate governance theory and organizational design theory. This article deals with finance and governance theories. We found out that Petrobras had, in the analyzed period, a financial performance below the expected for that group. Mistaken decisions regarding the regulatory model, the project portfolio, the business plans, the capital structure and the prices practiced for byproducts were decisive in this result.