13-214.2.

Subsection (a) sets the basic deadline for claims against a person, partnership, or corporation registered under the Illinois Public Accounting Act, or their employees, partners, members, officers, or shareholders, for an act or omission in performing professional services: the action must be commenced within 2 years from when the person bringing it knew or should reasonably have known of that act or omission.

Subsection (b) adds a repose ceiling of 5 years after the date of the act or omission — but with a targeted exception: if an income tax assessment is made, or a criminal prosecution is brought, against a person because of the accountant's work, that person may sue the public accountant who prepared the tax return within 2 years from the date of the assessment or the conclusion of the prosecution, even outside the ordinary 5-year window.

Subsection (c) extends the timeline for minors and people under legal disability: if the person entitled to sue is under 18 or under a legal disability when the claim accrues, the period doesn't start running until the disability is removed. The section applies to causes of action accruing on or after its own effective date.