In re Marriage of Sisk, 2019 IL App (1st) 181298-U

1. Case citation and parties
- In re Marriage of Sisk, No. 1-18-1298, 2019 IL App (1st) 181298-U (Feb. 1, 2019) (Rule 23 order; non-precedential).
- Petitioner-Appellee: Angela Sisk. Respondent-Appellant: Timothy A. Sisk.

2. Key legal issues
- Whether a reduction in the paying parent’s income (from $169,680 to $150,000) constituted a “substantial change in circumstances” under 750 ILCS 5/510(a)(1) warranting modification of child support.
- Whether the trial court improperly applied a 20% threshold (drawn from 750 ILCS 5/510(a)(2)) when denying modification.
- What income components (salary, employer reimbursements, fringe benefits, partner contributions) are relevant to the modification analysis.

3. Holding/outcome
- Affirmed. The trial court did not abuse its discretion in denying Timothy’s motion to reduce child support; the roughly 12% salary decrease was not a “substantial change” under section 510(a)(1). The court did not improperly apply a 20% rule (section 510(a)(2)’s 20% benchmark applies only in limited DHS enforcement cases).

4. Significant legal reasoning
- Standard of review: abuse of discretion for child support modifications. The appellate court gives trial courts broad latitude to weigh evidence and determine substantiality.
- The court evaluated the full financial picture: salary, employer reimbursements and benefits (noting statutory treatment of such reimbursements as income, 750 ILCS 5/505(b)(3.1)(b)), retirement contributions, housing purchase and down payment, living expenses, and the domestic partner’s financial contributions toward household costs.
- The 12% income reduction was modest given Timothy’s high income and partially offset by other resources; periodic income changes do not automatically warrant modification—the statute requires a “substantial” change.
- The trial judge’s isolated reference to “12%” and “not 20%” did not amount to reversible error; the judge clarified he did not mechanically apply a 20% rule.

5. Practice implications for attorneys
- When seeking or opposing modification, present a comprehensive financial record (salary, bonuses, reimbursements, fringe benefits, retirement contributions, housing, partner support) so the court can evaluate substantiality in context.
- Don’t assume a fixed percentage will control—argue substantiality relative to overall financial situation and child’s needs; a modest percentage drop at high incomes may be insufficient.
- Remember section 510(a)(2)’s 20% benchmark is limited (DHS enforcement cases) and is not a universal safe harbor.
- File promptly after a material change and quantify offsets (partner contributions, new benefits) to avoid delay undermining modification claims.
- Expect deferential appellate review of trial-court factfinding in child-support modifications.