uniformly allow reduction of gross income for cost of goods sold, though the computation of this amount may be subject to some modifications. Most states provide for modification of both business and non-business deductions. All states taxing business income allow deduction for most business expenses. Many require that depreciation deductions be computed in manners different from at least some of those permitted for federal income tax purposes. For example, many states do not allow the additional first year bonus depreciation deduction. Most states tax capital gain and dividend income in the same manner as other investment income. In this respect, individuals and corporations not resident in the state generally are not required to pay any income tax to that state with respect to such income. Some states have alternative measures of tax. These include analogs to the federal Alternative Minimum Tax in 14 states, as well as measures for corporations not based on income, such as capital stock taxes imposed by many states. Income tax is self assessed, and individual and corporate taxpayers in all states imposing an income tax must file tax returns in each year their income exceeds certain amounts determined by each state. Returns are also required by partnerships doing business in the state. Many states require that a copy of the federal income tax return be attached to their state income tax returns. The deadline for filing returns varies by state and type of return, but for individuals in many states is the same as the federal deadline, typically April 15. Every state, including those with no income tax, has a state taxing authority with power to examine (audit) and adjust returns filed with it. Most tax authorities have appeals procedures for audits, and all states permit taxpayers to go to court in disputes with the tax authorities. Procedures and deadlines vary widely by state. All states have a statute of limitations prohibiting the state from adjusting taxes beyond a certain period following filing returns. All states have tax collection mechanisms. States with an income tax require employers to withhold state income tax on wages earned within the state. Some states have other withholding mechanisms, particularly with respect to partnerships. Most states require taxpayers to make quarterly estimated tax payments not expected to be satisfied by withholding tax. All states impose penalties for failing to file required tax returns and/or pay tax when due. In addition,