Core Illinois Sources

• 215 ILCS 5/143a and 143a-2 — uninsured and underinsured motorist coverage.
• 625 ILCS 5/7-601 et seq. — compulsory automobile liability insurance.
• 735 ILCS 5/2-1116 — modified comparative negligence.
• 215 ILCS 5/155 — insurer vexatious-delay remedies.

Leading Illinois Decisions

• Thounsavath v. State Farm Mutual Automobile Insurance Co., 2018 IL 122558 — mandatory UM/UIM coverage and invalid named-driver exclusion as applied to the named insured.
• Bruder v. Country Mutual Insurance Co., 156 Ill. 2d 179 (1993) — enforceability of clear anti-stacking provisions.
• Hobbs v. Hartford Insurance Co. (Ill. 2005) — UIM stacking and policy ambiguity.

Illinois UM/UIM analysis should be tied to current Insurance Code text, mandatory-insurance rules, later appellate treatment and the policy’s limits, anti-stacking clauses and endorsements.

Publication review note — September 17, 2026. Confirm subsequent history, statutory amendments and current policy language before reliance.