A professional corporation rests on one idea: one shingle, one licensed profession. The One-Shingle Check below tests the profession, the people and then the filings. Fees are on the rules and numbers page; the overview explains the law.
The One-Shingle Check
- Name the one profession. The corporation renders one category of professional service or a listed related combination. Section 3.6 has two conflicting 2026 versions, so check the current text on ilga.gov.
- Confirm the route. IDFPR's checklist sends law, real estate, public accounting, design, security and salon businesses to other applications, and lawyers go through the Supreme Court.
- Test every person. The Act requires shareholders, directors, officers, agents and employees to be licensed in the category, apart from the secretary, supervised support staff and a registered agent with no other role.
- Check the stock. Shares go only to licensed or legally authorized individuals, with no voting trust or outside proxy.
- File the articles. Send form BCA 2.10(PSCA) and $150 to the Secretary of State, in person or by mail, with a permitted name ending.
- Register each location. Apply to the regulating authority before opening, paying $50 per location and per assumed name at a different address.
- Plan the redemption terms. The Act calls for the articles, bylaws or an agreement to cover buying back a deceased or disqualified shareholder's shares.
- Calendar renewal. Renewal is $40 with a notarized shareholder-license certificate. The Act and IDFPR's checklist give different expiry dates, so confirm with the regulator.
Common mistakes
- Treating the articles as the whole job and skipping the regulating authority's registration.
- Using the IDFPR corporation application for a business with its own route, such as accounting, law, design, real estate or salons.
- Filing one registration for several locations.
- Letting a non-licensee hold shares, a proxy or management authority.
- Missing the shareholder-license certificate at renewal.
- Assuming the corporation protects a professional from personal malpractice liability.
When to talk to an attorney
- Choosing among a professional corporation, a professional LLC or another structure.
- Reading Section 3.6 after the 2026 amendments.
- Buy-sell and redemption terms, or the death of the last shareholder.
- Adding unlicensed owners, management companies or investors, or forming a lawyer-owned entity.
- Board discipline or an IDFPR notice of violation.
A CPA cannot answer these questions. A CPA can help with the payroll, tax and accounting side of a professional practice and works alongside the owner's attorney. Physicians can also use the Medical Corporation Act guide and our physicians and healthcare professionals page.
Frequently asked questions
Is a professional corporation the same as a professional LLC?
No. A professional corporation is a corporation under 805 ILCS 10. A professional LLC is a limited liability company under 805 ILCS 185 that provides services needing an IDFPR license, with its own IDFPR registration. The LLC Act guide covers ordinary LLCs.
Do CPA firms register as professional corporations with IDFPR?
IDFPR's checklist sends public accounting firms to a Public Accounting Firm application instead. Section 14.4 of the Illinois Public Accounting Act sets its own firm-license ownership rules and does not say a CPA firm must be a professional corporation; the section is shown as scheduled for repeal on January 1, 2029.
Does a professional corporation protect me from malpractice claims?
Not for the professional's own acts. Each shareholder, officer, agent or employee stays personally liable for their own negligent or wrongful acts and those they directly supervise. The corporation is liable up to the full value of its property.
How often does a professional corporation renew?
The Act sets IDFPR renewal on January 1 of every third year, next in 2028. IDFPR's checklist says registrations expire December 31 every year. Because the two conflict, confirm the date and amount in License Lookup.
Official sources
- Illinois General Assembly: Professional Service Corporation Act, 805 ILCS 10
- IDFPR: Professional service corporation user guide
- IDFPR: Professional Service Corporation
- Illinois General Assembly: Illinois Public Accounting Act, 225 ILCS 450
This page is a plain-language summary. The official source controls if there is any difference.