Of all the numbers involved in selling a home by auction, the reserve is the one owners think about most and talk about least. It is the figure below which the property will not be sold under the hammer, and it is the line that turns a lively morning of bidding into either a sale or a pass-in. Understanding how it is arrived at, and when, takes a good deal of the anxiety out of auction day.

The first thing to know is that the reserve is not fixed at the start of the campaign. In Victoria, sellers set it in writing shortly before the auction begins, usually on the morning itself or in the days just prior. That timing exists for a reason. A sales campaign gathers information every week: how many groups walk through the open homes, how many take a contract away, how many order building inspections, how many ask about settlement terms. All of that feedback tells you far more about what buyers will actually pay than any estimate made before the first advertisement went live.

The starting point is comparable evidence. Recent sales of similar homes in similar streets, adjusted for land size, condition, orientation and any obvious differences, give a realistic range. In Melbourne’s north that comparison work matters, because two homes on the same street can sit well apart in value once you account for a renovated kitchen, a second bathroom, a rear lane, or a block that can take a garage. Agents in Victoria must also provide a statement of information with an indicative selling price range and the three most comparable sales, so the evidence behind the guide is on the table from the beginning.

The campaign then either confirms that range or challenges it. Strong attendance and several buyers seeking contracts suggests genuine competition and a reserve that can sit toward the upper end of the range. Thin attendance, or interest that never converts into serious questions, points the other way. Setting a reserve that ignores four weeks of quiet feedback rarely improves the result. It simply moves the negotiation from the footpath, where competition is public and buyers push each other, to a private conversation afterwards where the seller has less leverage.

There are legal boundaries to be aware of. The reserve must be consistent with the advertised price range; it cannot be set materially above the quoted figures, because underquoting rules in Victoria are designed to prevent buyers from being drawn to campaigns they were never in a position to win. Consumer Affairs Victoria enforces those rules. If your expectations have moved during the campaign, the honest path is to update the quoted range and let the market see it.

It also helps to think about what happens if bidding stops short. When the highest bid sits below the reserve, the property is passed in and the highest bidder usually gets the first opportunity to negotiate. That is not a failure, and plenty of homes sell within the hour. But the tone of that conversation depends heavily on how far apart the two figures are. A small gap is easily bridged; a very large one tends to end the day without a result.

Sellers sometimes ask whether to keep the reserve secret. In practice it stays confidential until the auctioneer announces the property is on the market, and that announcement is itself a signal that draws in hesitant bidders who have been waiting to know the home will actually sell. Holding a reserve too high for too long can cost you the very bidders who would have pushed the price along once they knew the sale was live.

The most useful mindset is to treat the reserve as the lowest price you would genuinely accept on the day, not as a wish or a target. Targets belong to the campaign; the reserve belongs to the decision. Talk it through with your agent using the evidence in front of you, consider your own timing and what you plan to do next, and take advice from your conveyancer or solicitor on the contract terms that sit alongside the number.

Set thoughtfully, a reserve gives an auction the one thing it needs most: a clear point at which everyone in the crowd knows the home is genuinely for sale.