IL SB1833

Amends the Illinois Income Tax Act to allow taxpayers to exclude from their base income the portion of income or loss from a trade or business conducted both within and outside Illinois that is not derived from or connected with Illinois sources

Allows similar exclusion for income or loss received from pass-through entities (such as partnerships or S corporations) conducting business both within and outside Illinois that is not attributable to Illinois sources

Applies to taxable years beginning on or after January 1, 2026

Determination of what constitutes Illinois-source income would be made according to the existing provisions in Article 3 of the Illinois Income Tax Act

Takes effect immediately upon becoming law