The sale prices of ancient coins jumped significantly over the past 3-4 years, which in turn resulted in a noticeable increase in the supply of coins coming to auction. I enjoy educating myself on different categories, and the increase in auction inventories are readily apparent for every category that I've investigated recently (Archaic, Achaemenid, Greek, Hellenistic, Roman, Celtic/Gallic, etc). However, coins of the Parthian Empire seem to be an exception. So far as I can tell, the number of coins showing up in auctions since 2020 might have actually decreased..... or at the very least remained constant. I don't know if there is an easily obtainable explanation for this, or if the trend that I'm observing is even accurate (maybe my data sets are skewed for some reason?). But these coins seem to be a fairly significant outlier in this respect, and it made me curious enough to run it by all of you for some thoughts.
SixBid's archive search can be useful for these kind of questions. When you search a term and click on the date range filter, it shows a distribution of the search results by year of the auction. Not every auction house will be included but I think it's likely a reasonably representative sample. https://www.sixbid-coin-archive.com/#/en/filter/search/dateRange?text=parthian
Interesting, I wasn't aware of this option, but it certainly looks like an efficient way of evaluating this type of data! Assuming that the last 3 bars represent the last 3 years, then this plot seems to support what I was thinking (no real increase compared to the 5 years prior). I'd of course need to pull up similar plots for the other categories to make sure that I'm not misinterpreting things in that direction. Admittedly, the majority of the information that I've pulled together is specific to NGC slabbed coins sold through Heritage. Not sure if those parameters play a role or not.
