When bidding more than the "estimated value", the winner can write off the difference between the value and their bid as a tax deductible donation. So that's on

When bidding more than the "estimated value", the winner can write off the difference between the value and their bid as a tax deductible donation. So that's one reason to not go too crazy with the valuation - a more reasonable market valuation can actually make the winning bid less expensive for the winner.