It was astounding enough when Bitcoin soared more than 14-fold over the course of 2017 to reach a peak of more than $19,000 on Dec. 16, giving it a total market value of $329 billion -- greater than the gross domestic product of South Africa or Ireland. Equally astounding, perhaps, is that Bitcoin’s value has now been eclipsed by the combined market caps of the next biggest four cryptocurrencies, which have largely moved in lockstep with Bitcoin’s (many) ups and (occasional jarring) downs. To believers in digital money, the emergence of competing coins, many with specialized uses, is a sign of the field’s maturation. To skeptics, it’s another sign that Bitcoin is in a bubble.
The four biggest, by market capitalization, are Ether (or Ethereum, as it’s often called), Ripple (aka XRP), Bitcoin Cash and Cardano. One of these, or another from the long list of up-and-comers, could potentially grab leadership away from Bitcoin and become the de facto digital coin of the future. Collectively, non-Bitcoin coins are known as altcoins. There are more than 7,500 such coins, or tokens, and about one in five of those are counted as full-fledged digital currencies, according to CoinMarketCap.com.