What signals that a bidder will not bid any higher?

A bidder signaling that they will not bid any higher typically involves a clear communication method that indicates their intention to opt out of further bidding. Declining the auctioneer's last call for bids is an unmistakable way for a bidder to convey this decision. When an auctioneer makes a final call for bids, those who do not respond or indicate they are out effectively communicate that they are finished bidding. This form of communication ensures clarity in the auction process, making it evident to both the auctioneer and other bidders that the individual is no longer participating.

Other methods, such as shaking their head or raising their hand, might not be as universally recognized or clear in the context of an auction and might lead to ambiguity. Although lowering a paddle may suggest a lack of interest in further bids, it does not explicitly communicate a decision as effectively as declining the last call does. Therefore, declining the auctioneer's request is the most definitive signal of a bidder's intention not to continue engaging in the bidding process.