Ancient Coins vs. U.S. coins?

I have been a serious U.S. coin collector since I was eight years old. That's almost half a century (gulp!). During this time, I have focused my interest almost exclusively on coinage issued through the U.S. Mint.

One field of study that has been on the periphery of my numismatic radar screen all these years is that of ancient coinage. The thought of owning a coin that thousands of years ago may have belonged to a Roman centurion is more than just a little fascinating.

However, I never really got into ancient coinage; heck I've always struggled to find time to devote to U.S. numismatics, so ancient coinage necessarily took a back seat. Besides that, the study of ancient coinage is so broad and complicated. To me, comparing U.S. coinage to the ancients is like comparing arithmetic to calculus. Where does one get started? My hat is off to those of you who are scholars of ancient coinage. The commitment of time and talent necessary to rise to your knowledge level is indeed admirable.

Over my long career as a coin collector, one common misconception I have observed amongst the general non-collecting population is that a coin's age is a key component of numismatic value. If that were true, just imagine what a coin from 300 BC would be worth!

As all experienced collectors know, there is no direct relationship between the age of a coin and it's collectible value. Rather, it all boils down to supply and demand. Simple as that.

While preparing this commentary, curiosity got the best of me. How do selling prices of Ancient coins compare to those of collectible U.S. coins? To gain some insight on this question, I employed the completed listings feature of eBay to evaluate some sales data.

I pulled numbers on the most recent 100 sales of ancient coins on eBay. I did likewise for U.S. coins in general, Indian Head cents, and Morgan dollars. I realize that in order to make this a truly valid scientific study, much larger sample sizes would have been required, due to the wide standard deviation inherent in these populations.

For non-statisticians, standard deviation measures the amount of variation from the average. A low standard deviation indicates the data points tend to be close to the average; a high standard deviation indicates the data points are dispersed over a large range of values. I could've calculated the number of data points (i.e. selling prices) necessary to legitimize this exercise as a scientific study, but I forgot where I put my statistical handbook from college, and I don't have the formula memorized anymore. Besides that, I just wanted a rough idea how prices of ancient coins fared against U.S. coins; I am not seeking to publish an article in a journal of statistics.

My findings are summarized in the table below:

Based on this data, we can conclude that in the universe of collectible coins for sale on eBay (is there any larger venue in the world for selling coins?) ancient coins are less than 10% as prevalent as U.S. coins, though ancients fare equitably when compared to smaller, but popular segments of the U.S. coin market, represented above by Indian Head cents and Morgan dollars. The average selling price per coin in the samples drawn is higher for ancients, though not by a huge factor. That pretty much disproves the concept that age is an important factor in determining a coin's value.

What is the highest price ever paid for an ancient coin? The highest price I found was $2.56 million, for something called an Hadrian Sestertius example. In comparison, the most valuable U.S. coin ever sold (that I know of) was a 1794 silver dollar that traded hands in January 2013 for an astounding $10.02 million! If anyone has updated information, please let me know.

Clearly, there is a bigger market for collectible United States coins compared to ancient coins. What's more, the upper stratosphere of U.S. coins is wider and reaches greater heights than that of ancient coins. Although the base of ancient coin collectors is smaller, there is a vibrant hobby spirit that has persisted literally for centuries. The healthy activity level of buying, the frequent number of big auctions, and numerous popular internet forums, all suggest a continued bright future for ancients. Of that, you can bet your last Denarius.