Personal Taxes

This is not a complete list but the following items may trigger the AMT. Itemized deductions such as taxes, interest, on home equity loans used for nonresidential purposes, medical expenses and miscellaneous investment or job expenses. Claiming a substantial number of exemptions for dependents or Certain tax-exempt interest, accelerated depreciation or incentive stock options.

The IRS’ recently-released statistics for the tax filing season. At income levels up to $100,000, fewer than 1% of taxpayers are in the AMT. For income levels between $100-200,000, this increases to 6%. After this At the $200,000 level up through $500,000, 70% of the taxpayers in this group are paying the Alternative Minimum Tax.
Unless Congress specifically addresses the issue with another AMT Patch, this

For Single or Head of Household the phase-out is $115,400 and is zeroed out at $323,000.
For Married filing jointly or Qualifying widow(er) the phase-out is $153,900 and is zeroed out at $477,100.
For Married filing separately the phase-out is $76,950 and is zeroed out at $238,550.

$51,900 for single and head of household taxpayers ($50,600 in 2012)
$80,800 for joint filers and qualifying widow(er) taxpayers ($78,750 in 2012)
$40,400 for married filing separately taxpayers ($39,375 in 2012)
There is an exemption phase-out for taxpayers with Alternative Minimum Taxable Income more than $115,400 for Single or Head of Household
$153,900 for MFJ or Widower
$76,950 for MFS.

The calculation of alternative minimum tax begins after the Adjusted Gross Income (AGI) is computed. The AMT is basically an add on to the normal income tax computation that is done. After you are done with the calculation of AGI, some of the preferential deductions (standardized or itemized) are added back into the AGI. Next a standard, flat alternative minimum tax deduction is deducted from the total. The remaining figure is known as AMT Taxable Income (AMTI). This AMTI is further taxed at different rates, instead of the current taxation rate. The output is the Tentative Minimum Tax (TMT), and in case if it exceeds the regular income tax the TMT is paid.

If you are Filing as Married filing separately, you must have lived apart from your spouse for the last 6 months of the year to take advantage of the dependent care, earned income, elderly credits and the $25,000 rental loss allowance.
Also Social Security will be 85% taxable.
Speak to your local CPA about the tax strategy of using married filing jointly or married filing separately.

If the filing status you are using for filing your individual income tax return is "married filing separately", and your spouse itemizes his or her deductions, then you must use your itemized deductions even if your standard deduction exceeds your itemized deductions.

Some spouses have had problems with the IRS in the past and still owe the IRS taxes. When you file a joint return, you and your spouse are both equally responsible for the taxes owed on that return. Any refund you might have been entitled to could be used to pay your spouses existing liability with the IRS or the state. Lastly, some people do not want their spouse to be aware of all of their financial involvement.

If you are filing as married filing separately, both persons must file using either the standard or itemized deduction amounts. One spouse cannot use the standard deduction and the other use the itemized deduction amount.