How to determine the market value of an ancient coin

When I purchase an ancient coin, I typically check with coinarchives to spot-check the market value history. However, I'm wondering how those that are in the business of selling ancient coins create their market price.

I've not found any work published on establishing a market value for an ancient coin. If you have anything, please post it. As a brainstorm in trying to figure it out myself, I've started down this rabbit hole:

From what I've perceived, the market value of an ancient coin depends on 'demand' + 'the intrinsic value of the metal', but what drives demand?

An obvious assumption would be that demand is based on a combination of the coin's rarity, historical significance, and condition. Is there anything else (beyond--I just want it...)?

If you agree, then would a formula such as the following work to categorize the asset's market value? If not, please chime in...

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Value = M + (R + HS) * C​

• M = The intrinsic value of the metal
• R = a value related to the rarity
• HS = a value related to the historical significance
• C = a factor related to the condition of the coin

The numbers below in yellow are placeholders, but the question is--could something similar to this model work to give novice collectors clarity for how much they should be spending on a coin?

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If the model works, I'll start identifying the data to try and find value market rates for each item in yellow.

let me know what you think...

 

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A rabbit hole indeed! Too many variables for me. Dealers fixed prices versus auction variable prices.
Dealers knowing that a scarce or rare coin for collectors needing only one coin to complete a set or subset is going to be priced accordingly, sometimes regardless of condition.
Coins that are scare today becoming common tomorrow when the latest hoard is discovered, etc.
I personally look at a coin across a whole slew of dealers offering one and ascertain the average for a certain condition of coin. Also I check AC Search for the auction results of said coin to form an opinion.
Good luck if you decide to go further with the model, it will certainly be interesting to see how it transpires.

 

I think that you've accounted for most of the important variables, but distilling it down to an equation that can be solved by plugging in values is probably an overly systematic approach. In short, it's more art than science.

And from the perspective of dealers, it is probably even more simple than that (little science, some art, and mostly bottom line). In short, I'd guess that they:

1. Do whatever they can to get the coins for as cheap as possible
2. Make a rough guess at what they are worth
3. Tack-on a liberal safety margin just in case they underestimated
4. Test the waters with inflated prices
5. Discount the asking price and entertain offers until they sell.

I suppose that metal prices would represent a kind of "floor" in extreme cases, but I don't think that people really take this kind of thing into account very often with ancients (Pay calculably more for a gold coin that weights 4.6g as opposed to 4.5g).

I tend to approach ancients in a fashion that is similar to modern "Type" collectors, where type is typically in reference to a person (bust of emperor for instance). The only thing that I care about is getting the best condition, best eye appeal coin that I can of that person, therefore, the significance of a specific reverse is unimportant to me (These would be analogous to modern coin "Key Dates" that are only important to "Set" collectors).

I then determine prices (that I will pay in this case) by putting together a data set of previous sales for coins that I find to be acceptably pleasing in different grade ranges (I buy slabbed coins). A linear cluster typically develops at the lower end, and then there are outliers that trend above that line. I remove the outliers, and the linear region is documented as the "Range". For instance, here is an example for Domitian Denarii graded AU where I determine my acceptable range to be $250-500 depending on how much I like the coin.



This probably doesn't help much with your specific inquiries, but it's a type of "pricing" process from a different perspective

 

I have had US coin-dealer friends who insisted that there had to be something comparable to the "Red Book" or "Grey Sheet" for ancients. AFAIK, there is no such thing. First, identify the coin, then search for what it is selling for on multiple websites.