It really depends on the auction house and who the bidder is. There is A LOT of behind the scene stuff that goes on, finagling, negotiations, etc, after the auction is over. New clients are checked out before hand and may have to put up a cc or deposit, also sign agreement to pay. Older clients who buy a lot are given far more leeway. Ultimately, if the winner doesn’t pay then the second highest bidder is offered the lot at their bid amount, sometimes days later, sometimes immediately or the lot is put up again at next auction. They track the auction process with notes during auction as well as audio and video so they know who the second bidder is.
I worked at a small, boutique auction house for many years.
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