Although private equity acquisition of short-term acute care hospitals purportedly improves efficiency and cost-effectiveness, financial performance after acquisition remains unexamined. We compared changes in the financial performance of 176 hospitals acquired during 2005-14 versus changes in matched control hospitals. Acquisition was associated with a $432 decrease in cost per adjusted discharge and a 1.78-percentage-point increase in operating margin. The majority of acquisitions-134 members of the Hospital Corporation of America, acquired in 2006-were associated with a $559 decrease in cost per adjusted discharge but no change in operating margin. Conversely, non-HCA hospitals exhibited a 3.27-percentage-point increase in operating margin without a concomitant change in cost per adjusted discharge. When we examined markers of hospital capacity, operational efficiency, and costs, we found that private equity acquisition was associated with decreases in total beds, ratio of outpatient to inpatient charges, and staffing (total personnel and nursing full-time equivalents and total full-time equivalents per occupied bed). Therefore, financial performance improved after acquisition, whereas patient throughput and inpatient utilization increased and staffing metrics decreased. Future research is needed to identify any unintended trade-offs with safety and quality.