It hasn't been a great week for digital currencies.
Bitcoin is trading nearly 40% below its record price of $64,000 following a sudden crash sparked by regulatory moves in China. Ethereum is down more than 35% from its all-time high, and dogecoin is off more than 45%.
Investors expect cryptocurrencies to be volatile. But the severity and breadth of the pullback has traders worried about a potential bubble, and observers are asking tough questions about whether coins are good stores of value.