[Financialization of the health sector in Brazil: theoretical and methodological challenges to the investigation of companies and business groups].

The article describes the history of the response to the theoretical and methodological challenges in research on companies and corporate groups in the Brazilian health sector that reorganized their shareholding structures, diversified their activities, and expanded their financial operations. Such movements in corporate concentration and expansion were analyzed with an approach to the frame of reference for financialization in contemporary capitalism in the analysis of selected companies and corporate groups. Corporate strategies were classified in three dimensions: shareholding, financial, and accounting structure and influence on the public agenda and the respective indicators orienting the organization of information from diverse sources for companies and corporate groups from 2008 and 2017. The study provides a profile of the intense and complex process of corporate reorganization in the health sector. Still, the study's exploratory design and difficulties in access to information and selection of companies and corporate groups mean that the observations are necessarily preliminary.