The Alternative Minimum Tax (or AMT) is an income tax system that parallels the ‘regular’ income tax system. Generally, under the AMT, all items of income taxable under the regular system are included and some additional items are included.  Numerous deductions allowed for the regular tax are not allowed for the AMT or they may be computed differently.  Numerous items of income or deduction may be reportable at times different than for the regular tax.  There is an AMT exemption which zeros out the AMT at lower levels of income.

Generally, all taxpayers are subject to the AMT.

No.  The AMT is calculated on a form for that purpose.  The form is only included in the tax return if the AMT exceeds the regular tax.  Individuals use Form 6251 and corporations use Form 4626.

The AMT tax rate for individuals is 26% on up to $175,000. of taxable income and 28% on any excess.  Individual long term capital gains have favorable tax rates as under the regular tax.