Washington: Ownership and Oversight
CPOM case law + the broadest co-ownership statute in the country. Washington bans lay control through case law but then deems some twenty categories of licensed health professionals to be rendering the "same professional services," letting physicians, PAs, ARNPs, chiropractors, and pharmacists co-own a single entity. Oversight is nearly as permissive: full ARNP independence and an hours-based PA collaboration model.
Who the statute actually covers
- The health-professions co-ownership list (RCW 18.100.050): professionals licensed under chapters 18.06, 18.22, 18.25, 18.29, 18.34, 18.35, 18.36A, 18.50, 18.53, 18.55, 18.57, 18.64, 18.71, 18.71A, 18.79 (nursing, including ARNPs), 18.83, 18.89, 18.108, 18.138, and 18.225 may co-own one professional service corporation.
- Stock and control limits (RCW 18.100.090, .080): shares only to licensed persons; the entity may render only its professional services. The 2023 amendment confirms co-ownership never expands anyone's clinical scope.
- "Collaboration agreement" (RCW 18.71A, as amended by 2024 c 62): the written agreement that replaced practice agreements; degree of collaboration is set at the practice level.
- Common-law CPOM: Morelli v. Ehsan, 110 Wn.2d 555 (1988): lay profit-sharing in professional practice is void.
1. Who can own what
| Entity / Path | Who may own | Key limits |
|---|---|---|
| Multi-professional PS corporation | Any combination of the listed health professionals, including physicians + PAs + ARNPs, may co-own one entity with no majority requirement for any profession. | Each owner still practices only within their own license; the Uniform Disciplinary Act (RCW 18.130) applies unchanged. |
| ARNP- or PA-owned practice | An ARNP or PA may solely own the professional entity; ARNPs practice independently within it, PAs operate under their collaboration agreements. | Structure the physician relationship carefully (FMV, genuine collaboration). |
| Lay / MSO ownership | Not permitted in the professional entity (Morelli); MSO model standard. | The constraint is control and profit-sharing, not the professional mix. |
2. Collaborative and supervisory oversight
| Role | Agreement required | Oversight mechanics | Path to independence |
|---|---|---|---|
| PA | Written collaboration agreement identifying at least one participating physician, signed by the physician(s) or employer (RCW 18.71A, 2024 c 62). | Hours-based model: under 4,000 postgraduate clinical hours, the PA works under supervision; at 4,000+ hours (with 2,000+ in the chosen specialty), the PA works in collaboration rather than supervision; a specialty change restarts a 2,000-hour clock. No numeric ratio, no statutory chart-review percentage. | Partial: supervision-to-collaboration shift at 4,000/2,000 hours; a collaboration agreement itself remains required. |
| NP / ARNP | None. Washington ARNPs have full practice authority: independent diagnosis, treatment, and prescribing including Schedules II-V, with no agreement, protocol, ratio, or chart review. | No physician involvement required at any point. | Independent from licensure. |
3. Primary authorities
- RCW 18.100.050 (2023 c 60); .080, .090.
- Morelli v. Ehsan, 110 Wn.2d 555 (1988).
- RCW 18.71A (2020 c 80 and 2024 c 62).
- RCW 18.79.
Practical read: Washington is the state where the clean lines blur on purpose: an NP, a PA, and a chiropractor can legitimately co-own the same entity that employs physicians. The compliance work moves from ownership percentages to scope discipline: every service traces to a licensee whose license covers it, and the lay-control line from Morelli still has teeth. Do not export Washington structures to any other state.
General education, not legal advice.