The already hot market of buying physician practices is about to get even hotter should Amazon’s proposed acquisition of One Medical win regulatory approval.

Amazon’s proposed $3.9 billion acquisition of One Medical, which was originally expected to close by the end of this month, comes during a period of unprecedented competition for primary care doctor practices with Walgreens opening hundreds of physician-staffed clinics with partner VillageMD while Walmart launches its doctor-staffed clinics under the Walmart Health brand in several new markets. Meanwhile, CVS Health, which has long staffed its more than 1,100 in-store clinics with nurse practitioners is also rolling out more primary care models that include physicians.

With Amazon’s backing, One Medical will have a huge financial war chest to expand into a primary care market that already includes well-capitalized hospitals and health systems that are buying up doctor practices along with the new retail rival entrants.

Retail healthcare companies are joining other non-traditional owners of doctor practices like private equity groups in gobbling up physicians, which isn’t expected to change in 2023.

In the case of Walgreens, the company is opening hundreds of doctor-staffed clinics through its $6 billion investment in the primary care company VillageMD while CVS has an array of outpatient expansions in the works from creating in-store HealthHubs with hundreds of new items to forming relationships with physicians to adding new healthcare services to the more than 1,100 CVS MinuteClinics across the U.S. that are staffed by nurse practitioners.

This year, Walmart has opened several new doctor-staffed “Walmart Health” centers in the lucrative Florida market. Like the healthcare services the retailer’s Walmart Health business has rolled out locations across Arkansas, Georgia and Illinois in the last three years, the Florida facilities will feature an array of primary medical services, urgent care including X-ray services, dental and eye care, and behavioral health services as part of a new model being replicated into other markets.