Because some taxpayers - particularly wealthy taxpayers - have been so successful in their efforts to legally minimize their tax bills, Congress came up with another way to tax them: the alternative minimum tax (AMT). The AMT provides a formula for computing tax that ignores certain preferential tax treatments and deductions that taxpayers would otherwise be entitled to claim.

So, many taxpayers are required to compute their income tax liability twice: once under the regular method and once again under the AMT method. An individual will be subject to the AMT if his or her AMT liability is more than the regular tax liability for the year.