Individual income tax: flow-through entities; sourcing and apportionment provisions; update. Amends secs. 102, 103, 105, 110, 112, 115, 122 & 123 of 1967 PA 281 (MCL 206.102 et seq.) & repeals secs. 111, 113, 114, 131, 132, 133 & 134 of 1967 PA 281 (MCL 206.111 et seq.).

HB 5484 updates Michigan's tax rules for businesses operating across state lines, specifically clarifying how income from flow-through entities (like S-corps and partnerships) is allocated to Michigan for tax purposes. It revises sections of the Income Tax Act to better define when income earned outside Michigan must still be taxed by Michigan, particularly for nonresident business owners. Key changes include refining rules for sourcing income from services performed in Michigan, business activities conducted within the state, and capital gains on property. This directly affects business owners with multi-state operations who must now follow updated guidelines to determine Michigan's tax share.