IL HB2554

Replaces term "taxpayer" with "complainant" throughout the Property Tax Code Section 16-55 to broaden who may file assessment complaints.

Establishes filing date rules for complaints: mail postmarked by deadline counts as filed on postmark date; delivery service shipments count as filed on date shown on tracking label; electronic submissions count as filed on date received if permitted by board rules.

Requires board of review to provide complainants at least 10 business days to cure deficiencies in complaint filings that don't comply with board rules, and must identify which rules were not met.

Mandates that when a change of $100,000 or more in assessed valuation is sought, intervenors and assessors must submit evidence supporting their positions no later than 5 calendar days before the hearing if board rules require advance evidence submission.

Allows board of review to permit parties to attend and participate in hearings by telephone or electronically.