Measuring private equity penetration and consolidation in emergency medicine and anesthesiology.

Private equity-backed staffing companies in anesthesia and emergency medicine, as well as those owned by publicly traded companies, gained notoriety for driving surprise billing-a practice where patients unexpectedly treated by an out-of-network provider can be billed for the difference between the provider's charge and what their insurer pays. Yet, little is known about the evolution of private equity and publicly traded company investment in these specialties. In this study, we construct a novel dataset identifying the ownership structure of anesthesia and emergency medicine physician groups to document trends in consolidation and the growing role of private equity and publicly traded companies. From 2009 to 2019, we found substantial increases in local market concentration in each specialty and that physician groups owned by private equity or publicly traded companies grew from 3.2% and 8.6% of the national anesthesia and emergency medicine markets, respectively, to 18.8% and 22.0%.