How to value a property you can't compare on the open market

The first question every off-market buyer asks is the hardest: with no asking price in lights and no comparable listings half a street away, how do you know what a private home is worth? The discomfort is understandable, and worth taking seriously, because pricing discipline is what separates a shrewd private purchase from an expensive mistake. But the absence of portal comparables is not the absence of evidence. It simply changes where the evidence lives.

What evidence should anchor a private valuation?

Start with what is verifiable. Land Registry records every completed sale, including off-market ones, so the sold history of the street is intact even where the marketing history is invisible; the limitation is lag, not existence. Per-square-foot benchmarks from genuinely comparable sold stock remain the spine of any defensible valuation, and a good agent or buying agent will hold the recent private comparables that never reached the public record. This is one of the quiet advantages of transacting through agents who work off-market routinely: they have seen the prices the portals have not.

Then adjust for what the open market systematically misprices. Condition and rarity carry more weight privately, because the discreet half of the prime market contains a disproportionate share of the best stock. A pristine house on a garden square has scarcity value that a portal algorithm, averaging across everything, will understate. The corrective is to weight comparables by quality, not just postcode and floor area.

Does buying privately mean overpaying?

The fear is that discretion is a seller’s trick to dodge price discovery. The evidence is more balanced. Hamptons’ research, reported in The Sunday Times, found buyers genuinely do pay more for private access, but knowingly, as the price of avoiding open competition for homes that may never appear publicly.

“Buyers have been willing to pay a premium to secure their home off-market and prevent sellers from marketing the property openly to other interested parties where competition is rife.”

Aneisha Beveridge, Head of Research, Hamptons, in The Sunday Times

A premium paid for certainty, speed and exclusivity is not overpayment; it is a different bundle of goods. The discipline lies in knowing which part of your offer is property value and which part is access value, and being honest with yourself about both. It also cuts the other way: without bidding theatre, private negotiations are often calmer and more rational, and around 30 per cent of off-market sellers eventually return to public marketing, which tells you their private price expectations met resistance. Buyers can and do say no.

The traps to avoid

Three recur. Anchoring on the seller’s number: with no public asking price, the first figure mentioned does disproportionate work, so arrive with your own valuation before you hear theirs. Comparing against asking prices rather than sold prices: portal asking prices are aspirations, and in a price-sensitive market they routinely drift down. And skipping process in the name of speed: a private purchase still deserves a full survey and proper legal diligence, because discretion is not a substitute for verification.

The structural answer to all three is to see enough private stock that no single property holds you hostage. That is what membership provides: flow, context and the comparables that never reach the portals. Position yourself properly, then register your brief.