wsky1

Valuation & confidence bands

How wsky1 turns real auction hammer prices into a daily point estimate and an honest low–high confidence band for every bottle.

Every bottle wsky1 tracks gets two numbers: a point estimate — the headline figure — and a confidence band around it. The band exists because a single hammer figure is false precision: auction prices for the very same bottle swing lot to lot on condition, fill level, label integrity, timing, and who's in the room. wsky1 shows that uncertainty instead of hiding it.

The point estimate

The point estimate is the most recent hammer price observed for that specific bottle. It's the same "latest" figure surfaced everywhere else in the app, so the portfolio total, the bottle page, and the public price pages all agree.

The confidence band

The band is the point estimate plus or minus a relative spread, measured from how much that bottle's recent comparable sales actually disperse:

  • wsky1 takes the bottle's hammer prices from the last 12 months. If there are fewer than 6 in that window, it widens to the bottle's full history rather than measure a spread off a handful of points.
  • With 4 or more sales it uses half the interquartile range over the median — robust to a single wild outlier. With 2–3 it falls back to the half min–max range. With fewer, it uses a default spread of 15%.
  • The spread is then clamped: never tighter than ±8% (even a bottle that has hammered once isn't treated as exact) and never wider than ±40% (so one outlier can't blow the band out to meaninglessness).

A tight, liquid name (say, Laphroaig 10) earns a narrow band; a thin or volatile one (a closed-distillery single cask) earns a wide one.

Example

A bottle whose latest hammer was £2,000, with a measured spread of 12%, is shown as:

£2,000   (£1,760–£2,240)

The band is formatted as a compact GBP range, e.g. £1,800–£2,400.

How often it updates

Valuations refresh daily against live auction data. On the Collector plan bottles get priority daily refresh and you can opt into price-change alerts; see pricing.

Your portfolio total

Your portfolio's headline value is the sum of every bottle's point estimate, shown against what you paid (when you've recorded a purchase price) as an absolute and percentage change — for example ▲ £420 (+12.3%) vs £3,400 paid.

A note on accuracy

wsky1 values bottles from observed auction sales — it is a measurement of where the market has cleared, not a guarantee of what yours will fetch. It is for informational purposes only and is not investment advice.

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