Sec. 1. (a) Each taxable year, a tax at the following rate of adjusted gross income is imposed upon the adjusted gross income of every resident person, and on that part of the adjusted gross income derived from sources within Indiana of every nonresident person:

(1) For taxable years beginning before January 1, 2015, three and four-tenths percent (3.4%).

(2) For taxable years beginning after December 31, 2014, and before January 1, 2017, three and three-tenths percent (3.3%).

(3) For taxable years beginning after December 31, 2016, three and twenty-three hundredths percent (3.23%).

(b) Except as provided in section 1.5 of this chapter (before its expiration), each taxable year, a tax at the following rate of adjusted gross income is imposed on that part of the adjusted gross income derived from sources within Indiana of every corporation:

(1) Before July 1, 2012, eight and five-tenths percent (8.5%).

(2) After June 30, 2012, and before July 1, 2013, eight percent (8.0%).

(3) After June 30, 2013, and before July 1, 2014, seven and five-tenths percent (7.5%).

(4) After June 30, 2014, and before July 1, 2015, seven percent (7.0%).

(5) After June 30, 2015, and before July 1, 2016, six and five-tenths percent (6.5%).

(6) After June 30, 2016, and before July 1, 2017, six and twenty-five hundredths percent (6.25%).

(7) After June 30, 2017, and before July 1, 2018, six percent (6.0%).

(8) After June 30, 2018, and before July 1, 2019, five and seventy-five hundredths percent (5.75%).

(9) After June 30, 2019, and before July 1, 2020, five and five-tenths percent (5.5%).

(10) After June 30, 2020, and before July 1, 2021, five and twenty-five hundredths percent (5.25%).

(11) After June 30, 2021, four and nine-tenths percent (4.9%).

(c) If for any taxable year a taxpayer is subject to different tax rates under subsection (b), the taxpayer's tax rate for that taxable year is the rate determined in the last STEP of the following STEPS:

STEP ONE: Multiply the number of days in the taxpayer's taxable year that precede the day the rate changed by the rate in effect before the rate change.

STEP TWO: Multiply the number of days in the taxpayer's taxable year that follow the day before the rate changed by the rate in effect after the rate change.

STEP THREE: Divide the sum of the amounts determined under STEPS ONE and TWO by the number of days in the taxpayer's tax period.

However, the rate determined under this subsection shall be rounded to the nearest one-hundredth of one percent (0.01%).

Formerly: Acts 1963(ss), c.32, s.201; Acts 1973, P.L.50, SEC.1. As amended by Acts 1979, P.L.68, SEC.1; Acts 1981, P.L.77, SEC.8; P.L.2-1982(ss), SEC.8; P.L.47-1984, SEC.4; P.L.390-1987(ss), SEC.37; P.L.192-2002(ss), SEC.70; P.L.81-2004, SEC.20; P.L.172-2011, SEC.54; P.L.205-2013, SEC.82; P.L.80-2014, SEC.9; P.L.212-2018(ss), SEC.20.