MI HB6351

Enacts the Multistate Tax Compact into Michigan law to facilitate uniform determination of state and local tax liability for multistate business taxpayers.

Establishes the Multistate Tax Commission composed of one member from each participating state to study tax systems, develop uniformity proposals, and perform cooperative audits among member states.

Provides that Michigan taxpayers subject to the Michigan Business Tax Act (2007 PA 36) must use that act's apportionment and allocation rules exclusively, rather than the compact's Article IV provisions.

Allows taxpayers with multistate income to elect either traditional state apportionment methods or the compact's standardized three-factor apportionment formula (property, payroll, and sales factors).

Includes provisions for uniform tax regulations, interstate audits, and binding arbitration to resolve apportionment disputes between states and taxpayers, with retroactive application to tax years after December 31, 2007.