Digital currency trading is exploding and daily volume could "soon" surpass that of Apple, according to a strategist closely followed by hedge funds.

"Cryptocurrency trading volume is now more than of $3bn/day on average, and will likely soon surpass that of the world's most liquid stock: Apple ($4bn/day),"Jens Nordvig, founder and CEO of Exante Data, said in a note Friday.

Nordvig said global daily trading volume between the two largest digital currencies, bitcoin and ethereum, into traditional currencies has multiplied eight times in the last year.

Bitcoin has surged this year, briefly increasing fivefold before tumbling amid a Chinese crackdown on digital currencies and criticism from JPMorgan Chase CEO Jamie Dimon this month. Bitcoin traded slightly lower near $3,524 midday Friday, but it is still up about 260 percent for the year, according to CoinDesk.

Many digital currency enthusiasts have noted that bitcoin is a way for new investors to access the growing number of digital currencies. Industry website CoinMarketCap lists more than 350 cryptocurrencies with a market value of more than $1 million each.

The total market value of all digital currencies was $121 billion Friday, according to CoinMarketCap.

Bitcoin price year to date

Source: CoinDesk

Ethereum traded mildly lower near $256, but was still more than 2,500 percent higher for the year, according to CoinDesk.

While digital currency trading volume has taken off, average daily trading volume in U.S. stocks fell in August to its lowest in three years, according to market researcher Tabb Group.

That said, Nordvig is still cautious on the often volatile digital currencies.

"We do not believe that one can predict with confidence at this point that any given cryptocurrency will continue to thrive and gain status as an alternative to traditional currencies in the long term," Nordvig said. "But we look forward to using the information from an increasingly active cryptocurrency market in our tracking of global capital flows, when appropriate."