Impermissible avoidance arrangement targets arrangements aiming to obtain tax benefit, invoking purpose and tainted element tests. An impermissible avoidance arrangement exists where the main purpose is to obtain a tax benefit and the arrangement exhibits one or more tainted elements: non arm's length rights or obligations; misuse or abuse of the Act; lack of commercial substance (or deemed lack); or non bona fide methods. A rebuttable presumption treats a step or part of an arrangement entered into for a tax benefit as establishing the main purpose. Tax benefit covers reduction, avoidance or deferral of tax, increases in refunds, treaty based effects, reductions in total income, and increases in loss.