Auction settlement
Trading & ordersAlso called: Auction market
The process by which the exchange sources undelivered shares through a separate auction session, in which other members offer the shortfall quantity for delivery to the original buyer.
In plain terms
An afternoon window on the settlement day, and you cannot bid in it — only members can. Whether anyone happens to offer your thin smallcap in that window is what decides between a modest loss and a close-out.