The Most Important Mailing List (That Auctioneers Aren’t Using)
I don’t think I’ve ever talked to an auction company that recorded that segment of their buyers. Online bidding platforms keep this information. These bidders shouldn’t be too hard to discover at on-site auctions, especially real estate ones. They’re already in your clerking software. All it’d take to capture this data is an extra column in your database to indicate that they came in second.