A cryptocurrency is a digital or virtual means of exchange. There are more than 6,700 cryptocurrencies today; among the better known are Bitcoin, Dogecoin, Ethereum, XRP, Tether, and Litecoin.
Unlike traditional currencies, virtual currencies currently operate without central authorities or banks, and they are not backed by any government. Cryptocurrencies are stored in "digital wallets" on a holder's computer or phone, or in the cloud. The wallet serves as a virtual bank account that enables holders to pay for goods and services or simply store the currency in hopes of an increase in value.
Cryptocurrencies defy neat categorization. They are not a traditional currency, commodity, or asset class, though they share characteristics of each.
There are several reasons why cryptocurrencies are not a traditional currency. Although some merchants have begun to allow cryptocurrency payments, they are generally not accepted as a medium of payment. Cryptocurrencies also are not used as a unit of account because prices, trade invoicing, and contracts are not quoted in digital currency units.
Finally, cryptocurrencies' ability to serve as a store of value—a safe instrument to preserve the value of people's financial wealth—is severely limited by their notorious volatility.
"The fact that cryptocurrencies are not issued by a central bank is actually the very reason why they can't achieve the quality of other well-accepted currencies," Mr. Aliaga-Díaz explained. "The role of a central bank is precisely to preserve the value of the currency by keeping inflation under control. That's why prices are more predictable under Federal Reserve management of the U.S. dollar money supply."
Cryptocurrencies share some characteristics of commodities. For example, they can be bought and sold in cash markets or via derivatives. But Mr. Aliaga-Díaz said they are not commodities because they are not physical raw materials.