Brazil's private health insurance market is the second largest in the world, behind only the United States, making it a valuable source of real-world evidence. This paper documents how physicians' inpatient reimbursement fees vary in the country and explores the relationship between these fees and the market share of health providers and health insurance companies. We implement a fixed-effects panel regression and take advantage of an unprecedented database that contains national administrative records of inpatient procedures paid by health insurance companies in 2016. We find a positive correlation between reimbursement for ICU procedures and provider market share. Conversely, we observe a negative correlation with insurers' market share. Additionally, we document substantial variation in procedure prices, both across and within Brazilian states, and observe that more competitive markets in Brazil tend to have higher population and GDP levels. Overall, our research enhances our understanding of the price setting dynamics of physician reimbursement fees in the context of a developing country. The insights gained from this study can assist policymakers in formulating appropriate regulations to ensure appropriate access to healthcare services.