In our last article we talked about the Alternative Minimum Tax item resulting from depreciation of business or rental property. A direct corollary of that issue is the AMT item that results from any subsequent sale or other disposition of such property. Critical to minimizing a taxpayer’s AMT is an understanding of the relationship between these two items.

When property is disposed of, a taxpayer calculates the gain or loss based on the difference between the selling price and his tax basis. For something like a stock or a bond, tax basis is the amount originally paid for the investment – that is all that is needed. This same concept also applies to the sale of business or rental property, but with one important difference – depreciation. In the case of depreciable property, tax basis is the amount originally paid, but then reduced for any depreciation taken.

The tax basis of depreciable property changes every year. In the example in the last article, a $10,000 machine was depreciated by taking a $4,000 deduction in the first year, and a $2,400 deduction in the second year. At the end of year 2, therefore, the tax basis of this machine was $3,600 ($10,000 less the $6,400 of total depreciation taken).

What would happen if the machine were sold at this point? The same basic principle of computing the difference between selling price and tax basis applies. Assume, for example, a sales price of $5,000. In this case the taxpayer’s gain would be $1,400, and this amount would be included in taxable income. This is the Regular Tax treatment.

The AMT item arises at the time of sale of property because, in general, a taxpayer uses a different method of depreciation for purposes of the Alternative Minimum Tax than is used for Regular Tax purposes. To the extent the taxpayer has these AMT items from differences in depreciation in prior years, the tax basis of that property similarly is different for the AMT than it is for the Regular Tax. Therefore, gain or loss on a sale of the property also is different. Essentially, the AMT difference in computing the gain or loss is a reversal of the Regular Tax-AMT depreciation differences in the past.

Continuing with the same example, if after two years a taxpayer has been allowed $5,100 in depreciation deductions for the AMT (see the prior article), the machine’s AMT tax basis is $4,900. Assuming a sale for $5,000, taxable gain for AMT purposes would be $100.

This $1,300 difference in taxable gain (the $100 of AMT gain compared to the $1,400 of Regular Tax gain) is an AMT item in the year of sale. This is a favorable adjustment in computing the taxpayer’s Alternative Minimum Tax. It would be entered as a negative number on the Form 6251, making Alternative Minimum Taxable Income $1,300 less than Regular Tax taxable income.

One out of every 14 AMT payers has this item, so it is important that both the Alternative Minimum Tax basis and the Regular Tax basis of depreciable property are properly calculated. Incorrect calculations can have the effect of negating other AMT planning that a taxpayer may have accomplished, costing real tax dollars.