MI HB4188

Reduces Michigan individual income tax rate from 4.25% to 4.15% effective January 1, 2018.

Beginning January 1, 2023, establishes automatic annual tax rate reductions when general fund revenue growth exceeds inflation rate, with reductions calculated using a specified formula based on revenue surplus and prior year collections.

Defines "capped general fund/general purpose revenue" using 2020-2021 fiscal year baseline adjusted by inflation multiplier of 1.425.

Requires state treasurer, senate fiscal agency director, and house fiscal agency director to determine revenue thresholds by January 2023 revenue estimating conference and annually thereafter using comprehensive annual financial reports.

Maintains existing provisions for school aid fund deposits (1.012% of gross collections divided by tax rate) and agricultural preservation fund deposits (3.5% of average farmland tax credits).