Estimating a wines value is a tricky business (there are loads of scientific papers on the subject, mostly crap if you ask me). As mentioned many times before on this forum, wine has no intrinsic value at all beyond the pleasure it can give (or as a chemical additive
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), thus we have to look at historical prices people are willing to pay.
A couple of points from my point of view only (not representative of the wine auction community as a whole, they may do things differently):
- Prices fall as well as rise which is why reserves are "suggested" to be set at less than the lower price range. At its base level its an agreement between what both the vendor and the auctioneer is comfortable with.
- Low values are usually the historical average sale price of the wine over a given period. Highs are .. well... the historical highs, again, its a grey area about the period of time, most of the time its the all time high.
- Low value aggregation is another issue. I personally use the published values from as many Australian auction houses as possible as well as my own (looking out for any anomalies and outliers), oh, and I generally ignore ebay prices, I find its not really representative of the mainstream wine market.
- I price wines with little or no history at the wholesale price OR if thats unknown then at 40% less than the lowest price as shown on the internet (professional wine searching option).