Why does my federal tax change with the basis of donated stock (to a non-profit) that I have held for far over one year?

[jrinaldo]

For a highly appreciated stock held for about 10 years, there is a significant change in the displayed tax owed when the basis is entered. Since the stock was held for over a year, the basis should not affect the deduction.

[CherylW]

If you've held your stock long-term, use the fair market value on the date you gave it away.

This, from IRS Publication 526, 

Property is capital gain property if you would have recognized long-term capital gain had you sold it at fair market value on the date of the contribution. Capital gain property includes capital assets held more than 1 year.

Amount of deduction—General rule.  When figuring your deduction for a contribution of capital gain property, you generally can use the fair market value of the property.