回复：how is the AMT credit work? Don't worry, here is the answer

To claim the AMT credit you need to have paid AMT in a previous year, and it has to be the right "flavor" of AMT. Generally this means you need to have paid AMT as a result of exercising an incentive stock option, or because of certain other "timing items" such as an AMT adjustment relating to accelerated depreciation. Any AMT you pay for other reasons, such has having a large number of exemptions or a large itemized deduction for state and local taxes, will not qualify you for the credit.