You Can't Use an LLC: The California Professional Medical Corporation Guide (2026)

Every entity-structure article on the internet — including good ones — starts from "LLC vs. S-corp," which makes them actively misleading for the roughly 120,000 physicians licensed in the largest physician state in the country. California's rules are categorically different, they got stricter on January 1, 2026, and the physicians most likely to stumble into the trap are exactly the ones this site serves: employed doctors adding side income, locums physicians structuring 1099 pay, and physicians launching DPC or cash-pay practices. This guide covers the legal architecture (why the ban exists), the Professional Medical Corporation's anatomy and formation process with real 2026 costs, the S-corp election math with California's 1.5% overlay honestly computed, and the anti-sales section no law firm's website will write: the income level below which you shouldn't form anything at all.

Why California Bans Physician LLCs: The Three-Layer Architecture

The prohibition isn't one statute — it's three interlocking frameworks, and understanding them explains every rule that follows.

Layer one: the Corporate Practice of Medicine (CPOM) doctrine. Rooted in Business & Professions Code §§ 2052 and 2400, California's CPOM doctrine — among the strictest in the nation — holds that only licensed individuals may practice medicine, and that unlicensed entities may not practice medicine, employ physicians to deliver care, or control clinical decision-making. This is the same doctrine covered in our Medical Director and CMO guide's MSO discussion, and the reason Kaiser's physicians work for physician-owned Permanente groups rather than the nonprofit health plan itself. A general corporation or LLC is an unlicensed entity; medicine practiced through it is medicine practiced by something that cannot hold a license.

Layer two: the Moscone-Knox Professional Corporation Act (Corporations Code §§ 13400–13410) — the legislatively authorized exception. Since 1968, Moscone-Knox has provided the one corporate form through which licensed professionals may practice: the professional corporation, with ownership, governance, and control locked to licensees. For medicine, that's the Professional Medical Corporation. Violating Moscone-Knox is itself treated as unprofessional conduct by the Medical Board — a discipline track separate from, and additional to, CPOM consequences.

Layer three: the explicit LLC bar. Corporations Code § 17701.04(e) closes the loop: no LLC — California-formed or foreign — may render professional services as defined in Moscone-Knox. This kills the two "clever" workarounds physicians ask about: there is no California PLLC statute (the PLLC simply does not exist here, unlike most states), and registering a Wyoming or Nevada LLC to practice California medicine fails identically, because the bar applies to foreign LLCs rendering services in California. Where you practice controls, not where you filed.

What actually happens if you use an LLC anyway: the entity's contracts with payers and facilities may be compromised; the Medical Board can pursue unprofessional conduct discipline; practicing medicine through an unlicensed entity implicates the Medical Practice Act's criminal provisions; and — the consequence with the sharpest teeth — a malpractice carrier discovering the noncompliant structure has an argument against coverage. None of this is theoretical enforcement trivia; it's the standard risk list California health law firms give clients unwinding exactly this mistake. If you've already formed an LLC for medical work, the path is dissolution (or conversion, with counsel) and proper re-formation — annoying, survivable, and far cheaper than discovering the problem during a payer audit or claim.

One clarification that saves many physicians the whole exercise: the ban is on entities, not on practicing without one. A California physician earning 1099 income as an individual — a sole proprietor filing Schedule C — is completely legal and requires no formation at all. Hold that thought; it's the foundation of the "when not to bother" section below.

Anatomy of a Professional Medical Corporation

A California PMC is a corporation formed under the General Corporation Law but bound by Moscone-Knox's overlay. The rules that make it "professional":

The 51/49 ownership rule. Under Corporations Code § 13401.5, at least 51 percent of shares must be owned by California-licensed physicians (MDs or DOs). Up to 49 percent may be held by a statutory list of allied licensed professionals — podiatrists, psychologists, registered nurses, physician assistants, optometrists, and others enumerated in the statute. Zero shares may be held by unlicensed persons — no spouse on the cap table, no investor, no MBA co-founder — with one narrow exception for assistant secretary/treasurer officer roles (not ownership) under § 13403. For the solo physician forming a PMC for side income, this is simple: you own 100 percent. For group practices and MD/NP ventures, the 51/49 architecture is the design constraint everything else fits inside.

Licensed-only, always. Every shareholder, director, and officer must generally be licensed. If a shareholder loses their license — discipline, death, retirement — their shares must be divested per statutory timelines, which is why competent PMC formations include buy-sell provisions handling exactly this from day one (the same buy-sell logic covered in our Partnership Buy-In Guide).

Single-profession purpose. The articles must state the corporation exists to practice medicine — specific purpose language is required, and the entity can't moonlight as your real estate holding company or unrelated consulting shell. (Non-clinical ventures — a pharma consulting arm with no medical practice, a rental property — can live in ordinary entities; it's the practice of medicine that must sit in the PMC.)

Name rules and the Fictitious Name Permit. The corporate name must comply with Moscone-Knox conventions (typically including "Medical Corporation," "M.D.," or similar signals). Practice under any brand name — "Golden State Direct Care" — and you need a Fictitious Name Permit from the Medical Board of California; operating a fictitious name without one violates the Medical Practice Act. Budget it into formation, and confirm all current Medical Board requirements directly at mbc.ca.gov — board-level requirements have changed over the years and are the item most likely to be stale in any online guide, including this one.

What the PMC does not do — say it plainly: it does not shield you from your own malpractice. California law does not permit a professional to launder personal professional liability through an entity; the corporate shield does not apply to your own negligent care. What the PMC does shield: personal exposure to the entity's contracts and leases, employee claims, business debts, and — meaningfully in group settings — vicarious exposure to co-owners' malpractice. Your malpractice coverage and the broader asset protection stack remain exactly as essential as before formation.

The 2026 Moment: California Just Codified CPOM

This guide arrives at a genuine inflection point. SB 351 (Cortese), signed October 6, 2025 and effective January 1, 2026, codified California's historically judge-made CPOM doctrine into statute — with provisions aimed squarely at private equity and hedge funds involved in physician practices: prohibitions on interfering with physicians' professional judgment, controlling clinical staff hiring, and dictating coding and billing procedures. Companion legislation (AB 1415) added pre-transaction notice obligations to California's Office of Health Care Affordability for MSOs and related entities in healthcare transactions.

Two practical implications for readers of this site. First, if you're evaluating a private equity approach to your practice, the California MSO-friendly-PC structure those deals rely on now operates under codified statutory limits with an enforcement-minded Attorney General behind them — 2026-era deal terms need 2026-era counsel, full stop. Second, and more broadly: California's direction of travel is tighter physician-entity enforcement, not looser. The era when a casually noncompliant structure sat unnoticed is the era that just ended — which is precisely why getting the entity right at formation, rather than retrofitting under scrutiny, is worth the modest cost documented next.

Forming a PMC: The Steps and the Real Costs

The formation sequence, per current California practice guides:

1. Choose a compliant corporate name and check availability with the Secretary of State.
2. File Articles of Incorporation on Form ARTS-PC (the professional corporation form, not the standard ARTS-GS) via the state's bizfile Online portal — $100.
3. Obtain a federal EIN — free, immediate, online.
4. Adopt professional-corporation bylaws with CPOM-compliant provisions (this is where a template built for Delaware startups fails you).
5. Hold the organizational meeting — elect directors/officers, issue shares consistent with the 51/49 rule.
6. File the initial Statement of Information within 90 days — $25, with recurring filings thereafter.
7. Obtain a Fictitious Name Permit from the Medical Board if using a practice brand name.
8. Register for payroll with the EDD (required once you pay yourself W-2 wages — yes, even as the only employee), plus local business licenses.

Call it roughly $2,000–$5,000 per year in true carrying costs for a lean solo PMC once formed (before the 1.5% income-based tax at higher earnings), against whatever the structure saves you. Which brings us to the only question that actually matters.

The Tax Decision: S-Corp Election, and the Honest California Math

A newly formed PMC defaults to C-corporation taxation — corporate-level tax plus dividend tax on what you extract, which is why nearly every physician PMC elects S-corporation status via federal Form 2553 (California honors the federal election; coordinate timing with your CPA). The S-corp's advertised magic: split your net income into a reasonable W-2 salary (payroll-taxed) and distributions (not payroll-taxed), saving employment tax on the distribution slice.

Here's what the generic version of that pitch omits, and what determines whether the PMC earns its keep — three honest adjustments:

Adjustment one: for most attendings, the savings are Medicare-only. As explained in our AI side-gig tax section, the 12.4% Social Security tax stops at the wage base ($184,500 in 2026) — and your primary W-2 already consumed it. For a moonlighting attending, the S-corp saves only the 2.9–3.8% Medicare tax on distributions. For a full-time 1099 physician whose S-corp salary is set below the wage base, real Social Security savings enter the picture and the math improves substantially.

Adjustment two: California charges rent. The 1.5% franchise tax on S-corp net income ($800 minimum) directly erodes the payroll-tax savings — the break-even income in California sits meaningfully higher than in Texas or Florida, and any analysis copied from a no-tax state overstates your benefit.

Adjustment three: the IRS polices the salary split. "Reasonable compensation" for a physician is the single most scrutinized element of physician S-corps — a cardiologist paying herself $60,000 in salary against $500,000 of collections is an audit invitation, and the defensible salary for physician work is high, which compresses the distribution slice the whole strategy depends on.

And one myth to retire: the entity does not unlock retirement space a sole proprietor lacks. The Solo 401(k) — including the Mega Backdoor Roth variant — works for Schedule C sole proprietors and S-corp owners alike, sharing the same $72,000 (2026) ceiling. Don't form a corporation to get a retirement plan you already qualify for; form it when the payroll-tax math above genuinely clears the carrying costs, as part of the broader physician tax plan.

Quick Reference: Your Situation, Your Answer

Employed California physician earning a few thousand to ~$75K in 1099 side income: No entity. Sole proprietorship, Schedule C, quarterly estimates, Solo 401(k). Revisit when income scales.

California physician who already formed an LLC for medical work: Stop billing medical services through it now; engage a California health law attorney to dissolve or convert and re-form correctly. Cheap to fix proactively; expensive to explain reactively.

Full-time locums or independent contractor physician in California: PMC with S-election is the standard, correctly. Form early in the year, set a defensible salary, get the EDD payroll machinery right, and read the locums tax guide alongside your CPA engagement.

Physician launching a branded cash-pay, DPC, or concierge practice: PMC + Fictitious Name Permit before you print the signage, with the DPC economics guide's Medicare opt-out analysis handled in the same counsel conversation.

Group formation, MD/NP venture, or anything with a non-physician "partner": This is bespoke 51/49 + CPOM architecture — attorney territory from the first conversation, not a filing-service project. Same answer, doubled, for anything involving an MSO or private equity under the new SB 351 regime.

Physician moving to California with an existing PLLC from another state: Your entity cannot practice here. Plan the California structure before the first California patient, not after.

Frequently Asked Questions