Patients' socioeconomic status on hospitals' efficiency in controlling for clinical component characteristics may have a role that has few been studied in rehabilitation centers. Because of the national health insurance system, rehabilitation centers are free of charge. To answer whether a patient's socioeconomic status (SES) is associated with efficiency and performance, we use a counterfactual analysis to get the patient's SES effect "as if" the patient's case was identical to whatever hospital. We restrained the data to patients from public acute care units where the decision on rehabilitation sector admission is based on availability, limiting bias by confounding factors. Besides, an analysis of six pathologies led to the same results. An exhaustive, detailed administrative database on rehabilitation center stays in France. To define the patients' socioeconomic status, we use two sources of data: the information collected at the time of the patient's entry into rehabilitation care and the information collected during the patient's stay in acute care. This double information avoids possible loss of socio-economic details between the two admissions. Patients recruited were exhaustively admitted over the year 2018 for stroke, chronic obstructive pulmonary disease, heart failure, or total hip replacement in France in the acute care unit and then in a rehab center. Mainly the elderly population. Information on patients' demography, comorbidities, and SES are coded due to the reimbursement system. Different dimensions controlling for factors (hospital ownership, patient clinical characteristics, rehabilitation care specificities, medical staff detailed information, and patients' socioeconomic status), were progressively added to control for any differences in baseline data between the two groups. We assess rehabilitation centers' efficiency by combining selected outcome quality indicators (Physical score improvement, Cognitive score improvement, Mortality, Return-to-home). The specific Providers' Activity Index is used to get the performance index. The performance of healthcare institutions is correlated not only to the case mix of their patients but also to the socioeconomic status of the patients admitted. The performance needs to be seen in light of patients' socioeconomic status. The data reveals that patients' socioeconomic status affects rehabilitation care efficiency and performance. In controlling patients' socioeconomic status, for-profit rehabilitation hospitals seemed more efficient than public ones.