Illinois Professional Service Corporation Act Guide
Learn how the Illinois Professional Service Corporation Act works: who may own a PC, who registers it, fees and renewal dates, with slides and tables.
Last reviewed October 29, 2026 · General information, not legal advice
General information only, not legal advice. CPA Tax Payroll and Accounting Corp is a CPA firm, not a law firm. Laws change: confirm with the official source or a licensed attorney before you act. Read the full notice.
The Illinois Professional Service Corporation Act, 805 ILCS 10, lets licensed professionals practice through a corporation, often called a professional corporation or PC. Articles go to the Secretary of State, and the profession's "regulating authority" registers the corporation: the Illinois Supreme Court for lawyers, and the Illinois Department of Financial and Professional Regulation (IDFPR) or another State agency for most others. This page is for licensed professionals and practice managers deciding on a PC.
Slide show: The Professional Service Corporation Act in seven slides
What the law does
It lets licensed professionals practice through a corporation. The Business Corporation Act applies, and this Act prevails where they conflict.
Who it covers
Individuals licensed in the same professional service, or in a listed group of related services. A professional service needs a license from a State agency, the U.S. Patent Office or the IRS.
The rule
Shareholders, directors, officers, agents and employees must all be licensed in the category, apart from the secretary and supervised support staff. Stock goes only to licensed individuals.
The number
Articles cost $150. Registration costs $50 per location, and renewal costs $40 (2026).
The deadline
The Act sets IDFPR renewal on January 1 of every third year, next in 2028. IDFPR's checklist says yearly, so check License Lookup.
The penalty
Late fees run $100 per unregistered year up to $500, then a civil penalty up to $1,000 after a hearing.
A practical tip
Confirm the profession's route first. IDFPR's checklist sends law, real estate, public accounting, design, security and salon businesses to other applications.
Who is covered
Question
Answer
Section
Who may organize
One or more individuals licensed in the same professional service or related services; an Illinois attorney may sign as initial incorporator
6
Shareholders, directors, officers, employees
Only individuals licensed in that category; exceptions for the secretary, supervised ancillary staff and a registered agent with no other role
3.1, 3.4(a)
Stock
Only to licensed or legally authorized individuals; no voting trusts
11
Lawyers
The Act applies only as the Supreme Court decides
16
Related professions
Certain combinations may share one corporation; Section 3.6 carries two conflicting 2026 versions, so check the current text on ilga.gov
3.6
How it touches your taxes and payroll
A professional corporation is a Business Corporation Act corporation. Federal C corporation tax is a flat 21%, and an S election is possible for eligible individual shareholders (up to 100, one class of stock, no nonresident aliens). Illinois charges a C corporation 7% income tax plus 2.5% replacement tax and an S corporation 1.5% replacement tax (2026). The regulator may discipline the registration for unfiled Illinois tax returns, unpaid tax shown on a return or an unpaid final assessment. See S corporation taxes and C corporation taxes.
