Since 2018, over 80K physician practices have changed ownership structure from independent (“physician-owned”) to ownership by an integrated delivery network (“hospital-owned”) or a corporate entity, like a health insurer, private equity firm, or large pharmacy chain (“corporate-owned”). The share of physicians working for health systems or corporations has risen from about 50 percent in 2018 to over 80 percent. Although corporate entities have acquired 2.5 times more physician practices than health systems have, health system employment of physicians has grown 2.7 times more than corporate physician employment, suggesting that corporate entities are buying smaller practices and reducing physician head counts at the practices they acquire. 
 
These figures can best by explained by economics and demographics. Physician-owners tend to seek health system employment for stability, as an insulation from rising costs. Corporate employment, especially by private equity firms, offers physician-owners a return on their investment and an exit opportunity. It is a natural business cycle for Baby Boomers to start a practice, grow it to maturity, and sell it to a private equity firm to fund their retirements. However, the prohibitive economics and administrative complexity of starting an independent physician practice these days makes young, entrepreneurial physicians far less likely to try. The market can still support the daily operations of independent practices, but it does not support their creation and strongly incentivizes their dissolution into parent organizations.