This glossary explains the core auction terms bidders and auction operators most often need to understand. Use it as a quick reference, then follow the related links for fuller explanations of live, timed, hybrid, and sealed-bid formats.
An opening bid is the first bid accepted on a lot when bidding begins.
Industry pages often use “starting bid” for the same idea. Christie’s defines starting bid as the opening amount at which bidding begins, while also noting that it does not have to equal the reserve price. Your page should acknowledge both labels to capture search intent.
A reserve price is the minimum amount the seller is willing to accept for a lot to be sold.
This is one of the most important trust terms in any auction. Christie’s and RICS both describe reserve as a confidential seller minimum below which the auctioneer cannot sell.
An online preview is the period before bidding opens, or before a live sale begins, when lots can be viewed and assessed.
Industry sources often use “viewing”, “preview”, “pre-sale exhibition”, or “catalogue publication” depending on sector. Online preview is the most practical digital term for users exploring lots before bidding opens.
A soft close is a timed-auction closing mechanism where a bid placed shortly before a lot is due to close automatically extends that lot’s closing time. This is also known as popcorn bidding.
The purpose is to prevent last-second sniping by ensuring that if bidding activity occurs within the extension window, the system adds time to the countdown and gives other bidders the chance to respond. The process continues until no further bids are received within that extension window.
Cascading lot closing is a timed-auction structure where lots close sequentially rather than all at once, each separated by a predefined gap from the previous lot.
This creates a more directed auction flow and lets bidders focus on the lot currently approaching close. The term is useful because it describes the closing schedule, not the extension rule.
A quick bid is the next valid bid shown by the platform based on the current price and increment rules.
A power bid is a high-speed bidding action designed to let a bidder place the next accepted bid quickly and confidently, usually in fast-moving or mobile-first bidding environments.
The exact interface can vary by platform, so this page should define the intent rather than overclaiming a universal industry standard. In practice, users often understand power bid as an accelerated way to participate without manually entering a custom figure each time.
Buy-it-now is a fixed-price purchase option that allows a buyer to secure a lot immediately without waiting for the standard bidding process to continue, provided the lot still qualifies for that option.
On iRostrum, this works as an optional rule rather than a replacement for auction logic. The page should explain when the button remains available, when it disappears, and how it interacts with current bid levels.
An offer is a proposal to buy a lot on stated terms, usually outside the standard next-bid flow or after a specific auction stage has ended.
This is a useful umbrella term because it can refer to post-auction offers, negotiated offers, or other structured proposals depending on how the platform is configured. An offer is not always the same as a live or timed bid.
Bid increments are the predefined steps by which bidding increases from one accepted bid to the next.
This is a core structural term because increments shape pace, bidder confidence, and price discovery. Christie’s defines bid increment as the set amount by which bidding increases during an auction.
A lot is the individual item, asset, or grouped set of items offered for sale as one unit.
Christie’s explains that a lot may be a single object or a group offered as one unit.
Hammer price is the final accepted bid price before buyer’s premium, taxes, fees, or other charges are added.
This term is widely understood across auction sectors. Christie’s defines it as the final bid price announced when the gavel falls. Your page should distinguish hammer price from total price paid.
A maximum bid is the highest amount a bidder authorises the system or auctioneer to bid on their behalf. This is also commonly known as a proxy bid.
Different sectors and platforms use “maximum bid”, “auto bid”, and “proxy bid” very similarly. For iRostrum, the page should make it clear that the bidder sets a ceiling, the system bids only as needed up to that level, and the final accepted price may still be lower than the ceiling.
A manual close is a governance rule where bidding can end or submissions can be captured, but the result remains pending until an authorised operator reviews the bid history and manually approves the winning bidder.
This is especially useful in hybrid, tender, and sealed-bid scenarios where the platform may need to consider more than price alone. The review can take account of bid conditions, finance attached to the bid, proof of funds, seller instructions, or other configured criteria before the winner is confirmed.
An offer after the auction is a post-sale attempt to agree a transaction on a lot that did not sell during the live or timed bidding process.
Some sectors describe this as aftersale, post-auction negotiation, or a post-auction offer. The key point is that the auction event has ended, but the seller may still accept a commercially valid proposal under the rules that apply after the sale.
