Income tax in the United States increase complexity, irrespective of the system's flatness or lack thereof. Income tax is also levied by most U.S. states and many localities on individuals, corporations, estates, and trusts. These taxes are in addition to federal income tax and are deductible for federal tax purposes. State and local income tax rates vary from 1% to 16% of taxable income. Some state and local income tax rates are flat (single rate) and some are graduated. State and local definitions of what income is taxable vary highly. Some states incorporate the federal definitions by reference. Taxable income is defined separately and differently for
Working Party on the Reorganisation of the Income Tax Act 1976 Following on from these reports the government in 1995 established a review process for rewriting the income tax legislation, overseen by an advisory panel drawn from the private and public sectors. The Income Tax Act has since been largely rewritten in a plain English style with a radically re-organised structure, including a unique (for New Zealand) alpha-numeric section referencing system (as opposed to the more usual numeric system. It was re-enacted as the Income Tax Act 1994 and again as the Income Tax Act 2007 as the various parts of the legislation was progressively rewritten. The Rewrite Advisory Panel was