Identifying the adequate level of financial viability refers to the most vital economic issues, since inadequate financial viability can result in the lack of resources for development, insolvency and bankruptcy of the company, but the surplus viability can impede development burdening the company with excessive reserves. The authors suggest introducing the concept of marginal values of financial viability indicators. In the course of research authors analyzed financial statements of service enterprises of Riga’s region for the period 2003-2008 and assessed actual, as well as marginal values of financial viability indicators, evaluated overall financial viability level of these enterprises for this period, analyzed deviation between actual and marginal values. The results were compared to actual bankruptcy tendency of Latvian companies, which verified objectivity of suggested methodology of financial viability indicators’ analysis. Suggested approach to determining lower and upper marginal values of company’s financial viability indicators can be considered as an effective tool for controlling company’s solvency level, estimating the risk of bankruptcy and choosing best possible alternatives for running economic activities in line with sustainable development.