Bid Ladder
Bid Ladder
The structured increment schedule that governs competitive bidding at auction
A bid ladder — sometimes called a bidding steps schedule — is a pre-defined table of minimum bid increments that an auction house applies across successive price bands during a sale. Rather than allowing bidders to advance a lot's price by any arbitrary amount, the ladder specifies exactly how large each upward step must be at a given valuation level: smaller, more granular increments at lower price points, and progressively larger steps as the hammer price climbs. The device is a cornerstone of orderly auction practice, used by every major saleroom handling fine jewellery and gemstones, from the international houses to specialist regional rooms.
Purpose and Rationale
The bid ladder serves several overlapping functions. First, it imposes discipline on the pace of bidding: without a fixed schedule, a room can descend into confusion as bidders call out irregular advances that are difficult for the auctioneer to track and for rivals to evaluate quickly. Second, it protects sellers by ensuring that competition moves the price upward in meaningful steps rather than allowing a lot to be secured for a trivially small advance over the previous bid. Third, it gives bidders — particularly those leaving absentee or telephone bids — a predictable framework within which to set their maximum figures, knowing precisely how many increments separate their limit from any given price point.
In the context of gemstone and jewellery auctions, where a single lot may carry a pre-sale estimate ranging from a few hundred pounds to several million, the ladder must span an enormous range. A typical published schedule might read as follows:
- Up to £1,000: increments of £50
- £1,000–£5,000: increments of £100
- £5,000–£20,000: increments of £500
- £20,000–£50,000: increments of £1,000
- £50,000–£200,000: increments of £2,000
- £200,000–£500,000: increments of £5,000
- Above £500,000: at the auctioneer's discretion
The precise bands and step sizes vary between houses and are revised periodically; the schedule in force for any given sale is printed in the catalogue conditions of sale and, increasingly, posted on the house's website prior to the auction.
The Ladder in Practice
During a live sale, the auctioneer is expected to follow the ladder strictly. When bidding crosses from one band into the next, the increment automatically adjusts upward, and the auctioneer announces the new step. A bidder who attempts to advance by a non-standard amount — for instance, offering £1,050 when the ladder calls for a move to £1,100 — will typically be refused, though the auctioneer retains discretion to accept unusual bids in exceptional circumstances, such as when a bidder is clearly attempting to reach a psychologically significant round number.
For telephone and absentee bids, the ladder is indispensable. A client leaving a written maximum bid of, say, £18,500 on a Kashmir sapphire lot knows that the room will bid on their behalf in the prescribed increments up to that ceiling. If the hammer falls at £18,000 against a single competing bid, the absentee bidder secures the lot at £18,000 — one increment below their maximum — rather than at the full ceiling. This mechanism, standard across major houses, means that understanding the ladder allows a sophisticated bidder to calibrate their maximum to land on a strategically advantageous step.
Variation Between Houses
While the underlying logic is universal, the specific schedules differ meaningfully between salerooms. The major international houses — Christie's, Sotheby's, Bonhams, and Phillips among them — each publish their own tables, and a bidder active across multiple rooms should consult each house's current conditions of sale rather than assuming uniformity. Specialist gemstone and jewellery auctions, such as those conducted by Gemfields or dedicated coloured-stone rooms, may use schedules calibrated differently from general fine-art sales at the same parent house, reflecting the price distribution typical of their lots.
Online bidding platforms that host jewellery and gemstone auctions — whether extensions of established salerooms or independent platforms — generally replicate the same ladder logic in their software, automatically presenting the next valid bid amount to the online participant. Some platforms display the full ladder as a reference table within the lot page, making the schedule more immediately visible than it often is in a printed catalogue.
Relationship to the Auctioneer's Discretion
Most conditions of sale include a clause reserving the auctioneer's right to depart from the published ladder when circumstances warrant. In practice, this discretion is exercised sparingly and usually transparently — for instance, when two determined telephone bidders are advancing rapidly on a significant coloured diamond or a top-quality Burmese ruby, the auctioneer may call larger steps to accelerate the climax of bidding, announcing the departure openly to the room. Conversely, when a lot is hovering just below its reserve, an auctioneer may accept a smaller-than-standard increment from a floor bidder in order to bring the price to a level at which the seller's reserve is met.
The auctioneer's management of the ladder is itself a skill: moving too quickly through increments can suppress competitive bidding by discouraging participants who feel the price has outrun them before they could respond, while moving too slowly can dissipate momentum and reduce the final hammer price.
Implications for Gemstone Buyers and Sellers
For collectors and dealers active in the coloured-gemstone market, familiarity with the bid ladder is a practical necessity rather than a procedural nicety. A buyer setting an absentee bid on a fine Padparadscha sapphire or an unheated Mozambican ruby should map their maximum against the applicable ladder to ensure it falls on a valid increment — or, if it does not, to decide consciously whether to round up to the next step or down to the previous one. Setting a maximum that falls between increments is not necessarily invalid, but the house will typically bid only to the last full increment at or below the stated maximum, which may result in the lot being lost by a single step.
Sellers, too, benefit from understanding the ladder when negotiating a reserve price with the specialist. A reserve set at an increment boundary is cleaner to administer than one set at an intermediate figure, and aligning the reserve with the ladder's structure can make the difference between a lot that sells cleanly and one that stalls awkwardly just below the hammer.