Do you need an MSO for your ABA practice in California?

California's corporate-practice doctrine

California enforces one of the strictest corporate-practice-of-medicine doctrines in the country. A general business corporation or an unlicensed person may not practice medicine or employ physicians to deliver medical care, grounded in the Medical Practice Act and the principle that a corporation has no professional rights (Cal. Bus. & Prof. Code §§ 2052, 2400). The same logic runs through the other healing-arts professions: licensed services must be delivered through a professional corporation formed under the Moscone-Knox Professional Corporation Act, owned and controlled by members of the relevant licensed profession, and California does not permit a limited liability company to render professional healing-arts services (Cal. Corp. Code §§ 13400-13410). The critical question for ABA, then, is whether behavior analysis is a licensed healing-arts profession in California at all.

ABA is not a licensed profession in California

It is not. California does not have a state license specifically for applied behavior analysts. BCBA certification through the Behavior Analyst Certification Board is the recognized professional standard, and the state's developmental-services system relies on that certification rather than a state license (BACB; California is absent from the state-by-state behavior-analyst licensure list). This single fact changes the entire ownership analysis. Because the corporate-practice doctrine and the Moscone-Knox ownership rules attach to licensed professions, and behavior analysis is not one in California, an ABA-only service is not caught by the professional-corporation ownership restriction. That is the opposite of the position in states like New York and Illinois, where an explicit behavior-analyst license and ownership rule force a licensee-owned clinical entity.

The fork that decides everything: diagnostics or not

Everything in California turns on which of the two ABA practice archetypes you operate, because the licensure that triggers corporate practice comes from the diagnostician, not the behavior analyst.

An ABA-only group that refers out diagnosis can be owned outright by a non-licensee founder or investor. A group that employs psychologists to perform diagnostic evaluations pulls the licensed psychology service inside its walls, and that service must be structured as a psychologist-owned professional corporation. Many scaled operators internalize diagnosis through a psychologist rather than a physician precisely because it is the least corporate-practice-intensive way to control the diagnostic gate. Which archetype you run decides whether you need the MSO structure at all.

Who is allowed to own the clinical entity

The answer splits by archetype. For an ABA-only practice, ownership is open: a non-licensee may own the entity in whole or in part, and it may be an ordinary corporation or LLC, because no California license gates behavior-analysis ownership. For the psychology-diagnostics service, ownership is restricted: the professional corporation that renders the psychological service must be owned at least 51% by licensed California psychologists, with any minority interest limited to the categories the Moscone-Knox Act allows, and it cannot be an LLC (Cal. Corp. Code §§ 13400-13410; California Board of Psychology). A non-licensee who wants an economic stake in a practice that includes psychology diagnostics therefore takes it in the management company, not in the psychology professional corporation.

What a management services organization actually is

An MSO is a separate company that provides the non-clinical side of a practice to a clinical entity it does not own. The clinical entity employs the licensed clinicians and holds the professional standing. The MSO employs everyone else and runs the business. A management services agreement ties them together, and the clinical entity pays the MSO a fee. In California, this structure is the standard way to place non-licensee capital alongside a licensed service, and it is the model physician and dental groups have long used. For an ABA practice, it becomes relevant specifically when a psychology professional corporation is in the picture, or when an operator wants a single management platform across multiple clinical entities.

When an MSO is required, and when it just helps

California is one of the few states where the honest answer is that an MSO may not be legally necessary. For an ABA-only practice, it is not required: a non-licensee can own the entity directly, so the MSO becomes a matter of preference, useful for building a management platform across sites or for a future transaction, but not a compliance requirement. For a practice with in-house psychology diagnostics, the MSO-PC structure is effectively required for any non-licensee capital, because the psychology corporation itself must be majority psychologist-owned and cannot take outside equity. And for any operator planning to bring in private-equity capital or to scale toward a sale, the MSO is where enterprise value accumulates, so it is built early even where not strictly required. Decide based on whether diagnosis is internal and whether outside capital is involved. See the practice expansion and sale page for the transaction view.

SB 351 and AB 1415: the private-equity and transaction rules

California tightened its healthcare-ownership environment in 2025, with two laws effective January 1, 2026. SB 351 codifies the corporate practice of medicine and dentistry into statute, barring a private equity group or hedge fund involved in any manner with a physician or dental practice from interfering with professional clinical judgment or controlling clinical decisions, and it limits post-transaction noncompete and nondisparagement clauses (SB 351 (2025), eff. Jan. 1, 2026). By its terms SB 351 reaches physician and dental practices, so it applies to any medical component of an ABA enterprise rather than to ABA or psychology services directly, but it signals the direction of California enforcement. AB 1415 is broader in reach: it expands the Office of Health Care Affordability pre-transaction notice framework to bring private equity groups, hedge funds, management services organizations, and entities that own, operate, or control a provider within the notice requirements for material change transactions (AB 1415 (2025), eff. Jan. 1, 2026). The materiality thresholds are still being defined by OHCA regulation, so any larger ABA transaction, especially one involving an MSO or outside capital, should be screened against the OHCA notice requirement.

How California would evaluate your arrangement

The questions California would ask depend on whether a licensed service is inside the practice. These are the factors that decide whether a structure holds up.

Fee-splitting and how to pay an MSO

Where a licensed service is involved, California prohibits paying or receiving consideration for patient referrals and treats fee-splitting with unlicensed parties as misconduct (Cal. Bus. & Prof. Code § 650). The safest management fee is fixed or cost-plus, set to fair market value, and traceable to documented services, rather than a percentage of the practice's professional revenue, which is more easily characterized as sharing in the licensed service's income. For an ABA-only practice with no licensed service, the fee-splitting concern is far weaker, but for Medi-Cal clients the federal anti-kickback statute applies regardless of how the practice is structured (42 U.S.C. § 1320a-7b(b)). Set the MSO fee to fair market value and document the services behind it.

Keeping clinical control on the right side of the line

Where the practice includes a licensed psychology service, the structure holds only while the MSO stays on the business side, holds no equity in the professional corporation, and the licensed psychologists keep genuine ownership and authority over diagnosis, treatment, supervision, and professional judgment. SB 351 now backs that line with statute for medical and dental practices, and the same principles guide psychology under the Board of Psychology's rules. For an ABA-only practice, clinical control is a quality-and-payor matter rather than a corporate-practice one, but the discipline of keeping business and clinical roles distinct still serves any future transaction. Write the documents so that clinical authority sits with the licensed clinicians.

How this connects to the rest of your compliance stack

Ownership is one layer. Three others interact with it directly, and getting the entity structure right does not resolve them:

• Payor and Medi-Cal disclosure. Your real ownership stack, including any MSO, is disclosed at enrollment and revalidation regardless of how it looks on paper (42 C.F.R. Part 455). See Medicaid and insurance mandates.
• Facility licensure. A change in the ownership or service model can affect facility and records obligations. See facility licensure and HIPAA.
• Entity structure. Choosing between an ordinary entity for ABA-only and a professional corporation for a psychology service is its own analysis. See entity structures for ABA practices.

Setting it up in California: the sequence

1. Decide the diagnostic model. Determine whether the practice will deliver psychology diagnostics in-house or refer them out, since that decides whether corporate practice applies at all.
2. Form the right clinical entity. For ABA-only, an ordinary corporation or LLC. For in-house psychology, a professional corporation owned at least 51% by licensed psychologists, not an LLC (Cal. Corp. Code 13400-13410).
3. Place non-licensee capital in an MSO. A standard corporation or LLC that contracts with the clinical entity and holds no equity in any professional corporation.
4. Set an arm's-length management fee. Fair market value, fixed or cost-plus, documented, and compliant with Bus. & Prof. Code 650 where a licensed service is involved.
5. Screen transactions for OHCA notice. Check any material transaction against AB 1415 and monitor OHCA regulations, and confirm SB 351 compliance for any medical component.

California MSO variables at a glance

Frequently asked questions