Where the figures
come from.

Sources

Auction results published by the houses themselves, among them Bring a Trailer, RM Sotheby's, Bonhams and Gooding Christie's. Every sale links to the house's own page for the lot.

Adverts from PistonHeads and the websites of UK specialist dealers, captured every morning.

UK registers: the DVSA's MOT history, which gives dated mileage readings the seller doesn't control, and the DVLA's counts of how many of a model are registered and taxed.

Exchange rates from the Bank of England.

Asking and achieved

An asking price is what a seller advertises. It is always called asking and never treated as a sale.

An achieved price is what a buyer paid at auction, the house's premium included. Where a house publishes only the winning bid, we add the house's own published fee and show both figures.

A car that leaves the market is shown as last seen. We don't say it sold. Lots that didn't sell, unsold high bids and estimates are never counted as sales.

No averages

We don't give an average or a middle price. Each sale and each advert is shown as itself, with its date and its source, so you can see the spread for yourself.

Currency

A sale in another currency is converted to sterling at the Bank of England rate for the sale date, or the last working day before it. Both figures are shown.

When figures update

Adverts are captured every morning. Auction results are added after each sale, once the house publishes them. Every page and every answer says the date its figures are as at.

When we are wrong

A house can misdescribe a lot, and an advert can carry a typing error. When we find a mistake we correct it, and the page shows the new date. If you find one, tell us at hello@supercarai.co.