AZ SB1109

Establishes annual income tax rate reductions for taxable years beginning December 31, 2021 and thereafter based on state budget surplus calculations.

Requires the joint legislative budget committee to calculate ongoing state general fund revenues and compare against a growth limit (fiscal year 2020-2021 revenues adjusted annually for inflation and population growth).

Directs the committee to estimate structural surplus when revenues exceed the growth limit, multiply that amount by 50%, and use the result to reduce income tax rates proportionally.

Amends section 43-1011 to reduce all tax brackets under the current rate structure by an equal percentage equal to the calculated surplus reduction amount, with no rate reductions if the calculated amount is zero or negative.

Defines key terms including growth limit, inflation (Phoenix consumer price index), population growth (U.S. Census Bureau data), and structural surplus for purposes of the rate reduction calculation.