Donors who purchase items at a charity auction may claim a charitable contribution deduction for the excess of the purchase price paid for an item over its fair market value. The donor must be able to show, however, that he or she knew that the value of the item was less than the amount paid. For example, a charity may publish a catalog, given to each person who attends an auction, providing a good faith estimate of items that will be available for bidding. Assuming the donor has no reason to doubt the accuracy of the published estimate, if he or she pays more than the published value, the difference between the amount paid and the published value may constitute a charitable contribution deduction.
