MI HB4183

Increases Michigan's motor fuel tax rate to 51 cents per gallon beginning January 1, 2026, up from the current inflation-adjusted rate structure that started at 26.3 cents in 2017

Continues annual inflation adjustments starting January 1, 2027, capping increases at the lesser of 5% or the inflation rate, rounded to the nearest 1/10 of a cent

Imposes a floor stock tax on motor fuel held in storage (over 3,000 gallons) as of December 31, 2025, equal to the difference between the 2025 and 2026 tax rates

Requires inventory reports and payment of the floor stock tax to be filed with the department by February 20, 2026

Takes effect only if Senate Bill 578 and House Bills 4180, 4181, and 4182 of the 103rd Legislature are also enacted into law