Reserve prices are the most misunderstood part of online auctions. New bidders see "reserve not met" and panic. Veteran bidders barely notice.
Here's what it means and how to think about it.
What is a reserve?
A reserve price is the minimum the seller will accept. It's hidden, neither bidders nor the public see the actual number. The auction listing only shows:
- ✓ Reserve met, current bid is at or above the reserve, the lot is going to sell
- ✗ Reserve not met, current bid is below the reserve, the lot will go unsold unless someone bids enough
If bidding closes with the reserve still not met, the lot is marked unsold. The high bidder doesn't win, they're released from the contract and pay nothing. The lot may be relisted in a future event.
Why sellers use them
Three reasons:
- Protection from a bad day. Sometimes an auction has only two bidders, the high bid stalls at £30, and the seller doesn't want to give a £200 item away for £30. The reserve guarantees they don't have to.
- Anchoring. A reserve forces bids to actually engage with the item's value, rather than camping at the starting bid.
- Conversion of "untested" or unusual items. When an item's condition is uncertain, a low starting bid with a meaningful reserve invites cautious bidders without forcing the seller into a fire sale.
The downside: a reserve set too high kills a lot. If bidders don't think it's worth it, they don't push, and the lot ends unsold. The seller gets nothing.
Why we hide the actual number
If you knew the reserve was £200, you'd bid £200 (one increment above whatever the current bid was) and stop. The seller never sees the actual top of the market.
Hidden reserves force you to bid as if you were trying to discover the price organically. Some bidders go higher than the reserve and the seller benefits.
How to bid against a reserve
The honest answer: bid your max, ignore the reserve indicator entirely.
The reserve only matters in two scenarios:
- You're the high bidder and the lot still shows "reserve not met" near close. Decide whether you want to push higher. If you set a max and the system never pushed you to it, the reserve is above your max, the lot won't sell.
- You're not the high bidder and the lot says "reserve met". It's going to sell. Decide whether to compete.
If a lot keeps reading "reserve not met" with little bidding, two interpretations:
- The seller set the reserve too high → fair price discovery never reaches it
- The market disagrees with the seller's idea of value → you're probably right not to push
In both cases, walk away. Don't talk yourself into bidding more just because there's a hidden number you want to satisfy.
The "reserve scam" myth
A persistent claim online: "sellers shill-bid up to their reserve". That would be illegal in the UK (Sale of Goods Act 1979, plus auction-specific rules under common law).
In practice on Biddurs:
- Sellers can't see who's bidding. Bidder identities are anonymised, even to admin, in the audit logs.
- Sellers can't bid on their own lots. We block accounts with admin-flagged consignor links from bidding on their own consigned lots.
- The reserve is set before bidding opens. It can't be raised once the auction starts.
So if a lot says "reserve not met" at £80, the reserve is genuinely above £80, not because someone is gaming the system.
What does UK law say about reserves?
The legal position is straightforward:
- Sellers may set reserves and are not obliged to disclose them
- Reserves must be set before the auction opens
- Auctioneers cannot accept bids known to be below reserve as final sale
- Shill-bidding (bidding on your own lot to drive up the price) is fraud
The auctioneer (us) is the agent of the seller, and the contract forms between buyer and seller once the hammer falls, assuming the reserve has been met. Below reserve, no contract.
When to skip a reserve auction
Personal opinion as a buyer: lots with no current bids and a vague description should be skipped if they have a reserve. Means the seller wants more than the market will give, and you're guessing what that "more" actually is.
The opposite of skip: lots with many bids and an unmet reserve. That signals the market is engaged, the reserve is plausibly close, and one more push might hit it. Set a generous max and let the proxy bidder discover whether you'd have won anyway.
A short rule
If you'd happily pay your max amount for the item regardless of what some hidden number is, bid your max and forget the reserve exists.
If the existence of a reserve makes you nervous about overpaying, the answer is to set a lower max, not to try to game an unknown.