In the span of just over a month, California Attorney General Rob Bonta has delivered a one-two punch to private equity-backed healthcare entities that should put every investor, MSO operator, and healthcare platform in the state on high alert. First, on March 30, 2026, the AG filed an amicus curiae brief in Art Center Holdings, Inc. v. WCE CA Art, LLC, laying out an aggressive interpretation of California’s corporate practice of medicine (CPOM) doctrine that strikes at the structural heart of the MSO-PC model. Then, on May 4, 2026, the AG secured a stipulation for final judgment and permanent injunction against Aspen Dental Management, Inc. — a national dental MSO — imposing sweeping operational restrictions, $2 million in civil penalties, $300,000 in patient restitution, and 36 months of compliance monitoring.
Taken together, these actions are not isolated incidents. They represent a deliberate, strategic enforcement posture by the state’s chief law officer — one backed by newly enacted legislation and aimed squarely at the structures that private equity has relied on for decades.
The Brief: Drawing a Line in the Sand
In his Art Center Holdings amicus brief, AG Bonta argued that stock transfer restriction agreements (STRAs) and restrictive MSA termination provisions — long considered standard and customary across the PE-backed healthcare industry — are themselves CPOM violations, regardless of whether the MSO has ever exercised those rights. The brief went further, asserting that the mere contractual reservation of the right to replace a physician-owner “causes an impermissible division of loyalties” and that liability extends to both the MSO and the physician-owners on an aiding-and-abetting theory. Perhaps most pointedly, the AG dismissed the defense that these arrangements are industry-standard, stating that “the fact that a practice is common or customary in an industry does not mean it is legal or immunize it from enforcement”.
The Stipulation: Enforcement with Teeth
The Aspen Dental stipulation demonstrates that the AG is not merely theorizing. The judgment permanently enjoins Aspen Dental Management from owning practice property, enforcing non-competes against clinicians, determining clinician salaries, controlling physician hiring, or basing service fees on practice revenue. It also mandates that practice owners can renegotiate — and walk away from — MSO services agreements annually. A compliance monitor will oversee adherence for three years. These are not theoretical guardrails; they are court-ordered restructurings of the MSO-practice relationship.
A Strategic Posture, Not a One-Off
These twin actions arrive on the heels of Senate Bill 351, signed by Governor Newsom on October 6, 2025, which codified CPOM restrictions as applied to private equity and hedge funds and granted the AG explicit authority to seek injunctive relief, equitable remedies, and attorneys’ fees in enforcement actions. Together, the new statute, the amicus brief, and the Aspen Dental judgment form a coherent regulatory strategy: legislate, articulate, and enforce. Market participants should view this as a signal that California’s enforcement infrastructure is now fully operational and pointed directly at PE-backed healthcare structures.
What This Means for Investors and Operators
Private equity sponsors, MSOs, and healthcare platforms considering acquisitions or expansions in California need to think very carefully about their exposure. The AG has made clear that structuring a deal with standard STRAs and long-term MSAs is no longer safe harbor — it may be the basis for an enforcement action. Existing market participants should proactively review their corporate structures, MSO agreements, and day-to-day operational practices for CPOM compliance risk. Document remediation is most effective and least costly when done proactively, rather than under the pressure of a dispute, transaction due diligence, or regulatory inquiry. And documentation is only part of the picture — operational practice, including how the MSO and PC interact day to day, is critical to compliance.
