The concept of intellectual capital (IC) management in modern conditions is considered a recognized tool of organizational management, which is designed to draw the attention of managers and ordinary employees to the problems of effective use of intellectual resources to achieve a competitive advantage. However, in practice, the perception of IC varies from a complete misunderstanding to the construction of the rank of the most priority areas of improvement of the internal control system. The purpose of this article is to develop an approach to the practical assessment of relational capital using social network structures and its application to the analysis of the case of the Russian service company, which faced the problems of inefficient knowledge management, leading to the loss of competitive positions. The study shows that the analysis of informality along with the study of formal organizational structure can give positive results in the diagnosis of current management problems, combining under the auspices of the IC personnel management techniques and design elements of the organizational structure. In general, the authors show that the analysis of informal networks can also contribute to the identification of relational capital and understanding of the problems of human capital development and improve the efficiency of internal knowledge exchange.