Scoring Auction Deals Against Adjusted Market Value
The Auction Price vs Market Value Calculator scores auction purchases by comparing the all-in cost to a multi-factor adjusted fair value.
For an $85,000 hammer price with 15% buyer's premium ($97,750 all-in), against $100,000 estimated value and $98,000 comps adjusted for trend, seasonality, supply/demand, sentiment, and liquidity, the deal score is 6.1% — meaning you're paying $6,354 below the $104,104 effective fair value.
The Fair Value and Deal Score Calculation
The calculator builds fair value in layers and compares it to your all-in auction cost:
Base Fair Value = (Estimated Market Value + Recent Comparable Sales) / 2
Adjusted Fair Value = Base x (1 + Trend%) x (1 + Seasonal%) x (1 + Supply/Demand%) x Sentiment Multiplier
Effective Fair Value = Adjusted Fair Value x (1 - Liquidity Haircut)
All-In Auction Cost = Hammer Price x (1 + Buyer's Premium%)
Deal Score = (Effective Fair Value - All-In Cost) / Effective Fair Value x 100
The liquidity haircut is 0.3% per month to market, capped at 12%.
Example: Scoring an $85,000 Auction Deal
An investor evaluating a collectible with an $85,000 hammer price, $100,000 estimated value, $98,000 comps, 2% trend, 15% premium, 10% volatility, 3% supply/demand, 1% seasonal, neutral sentiment, and 3-month time to market:
| Step | Calculation | Result |
|---|---|---|
| Base Fair Value | ($100,000 + $98,000) / 2 | $99,000 |
| Adjusted Fair Value | $99,000 x 1.02 x 1.01 x 1.03 x 1.00 | $105,049 |
| Liquidity Haircut | 3 months x 0.3%/mo | 0.9% |
| Effective Fair Value | $105,049 x (1 - 0.009) | $104,104 |
| All-In Auction Cost | $85,000 x 1.15 | $97,750 |
| Deal Score | ($104,104 - $97,750) / $104,104 | 6.1% |
| Volatility Band | $104,104 +/- 10% | $93,694 - $114,514 |
The 6.1% deal score indicates a favorable purchase — you're paying $6,354 below effective fair value, with your all-in cost sitting in the lower third of the volatility band.
When Deal Scores Mislead
A positive deal score doesn't guarantee profit.
The model is only as good as its inputs — overstated market values or stale comps inflate fair value artificially.
Always verify comparable sales are recent (within 6 months), genuinely similar, and from arms-length transactions.
Also factor in resale costs (seller's commissions, shipping, insurance) which can easily erode a 5-10% deal score.