after , including a reduction in the u.s . federal corporate income tax rate from 35% ( 35 % ) to 21% ( 21 % ) . the 2017 tax act makes broad and complex changes to the u.s . tax code including , but not limited to , the repeal of the irc section 199 domestic production activities deduction in 2018 and accelerated depreciation that allows for full expensing of qualified property beginning in the fourth quarter of 2017