What is a soft close (or dynamic ending)?

If someone places a bid in the last few minutes of an online auction, the end time for the specific lot is extended. The process continues until there are no more bids made within the last minutes or seconds. At that point, that specific lot closes. The overall auction continues until each lot has no advance. Oftentimes, online auction companies wills stagger the end times on each of the auction’s items so all lots do not close at the same time.

For example: Lot 1 has a closing time of 7:00 p.m. At 6:30 p.m. Bidder A places a bid. The auctioneer has set the bidding to extend if any bids are made within the last two minutes. At 6:59 p.m. Bidder B outbids Bidder A. The countdown clock resets and now Lot 1 will close at 1:01 p.m. Bidder A and any other bidder have the opportunity to bid. If no bid is made within that last two minutes, the auction for Lot 1 closes and Bidder B wins the lots. If a bid is made, the clock starts over again. 

Why do auctioneers use it?

Auction professionals will use a soft close and/or staggering lot ending times to mimic the back and forth of a live auction. More importantly, this technology allows for every bidder an opportunity to advance their bid. This more faithfully captures the true competitive nature of an auction and eliminates sniping or other online strategies or technologies.