Amid a sell-off in the cryptocurrency markets that began Wednesday, Bitcoin's market capitalization fell below the $100 billion mark on Thursday — a level not seen since October 2017.
As of 3:26 p.m. HK/SIN (2:26 a.m. ET Thursday), the market cap of Bitcoin stood at $98,194,458,586, according to Coinmarketcap.com.
That move came after a major sell-off in the cryptocurrency markets on Wednesday, which continued into Thursday in Asia.
BKCM founder and CEO Brian Kelly told CNBC's "Fast Money" on Wednesday that the sharp downturn had to do with bitcoin cash, which splintered off in August 2017 from regular bitcoin with the goal of being able to process more transactions.
Bitcoin cash is doing a "hard fork" or "effectively a software upgrade," the cryptocurrency fund manager said. "When you do a software upgrade, everybody usually agrees. But in this particular case, everybody is not agreeing."
As of 3:29 p.m. HK/SIN (2:29 a.m. ET Thursday), Bitcoin stood at $5,564.70, according to Coindesk. Bitcoin had been trading comfortably around the $6,400 range for the majority of the fall, in stark contrast to the volatility it experienced the rest of the year.
It is likely only the second time the two cryptocurrencies have traded near the same level, although it is difficult to state with precision the historical market capitalizations of most digital coins.
As of 3:30 p.m. HK/SIN Thursday (2:30 a.m. ET), XRP's market cap was at $18,722,821,459, compared with Ether's $18,560,372,901, according to data from Coinmarketcap.com.
Data from Coindesk also showed XRP having a higher market cap of $18.44 billion, versus Ether's $18.26 billion.
One possible reason behind the recent move was due to the perception that Ripple, the company behind XRP, has "made a lot of progress," Zennon Kapron, director at financial technology consultancy Kapronasia, told CNBC over the phone.
As Ripple has generally gotten more traction and "a lot of people are very bullish on XRP," Kapron said. However, he added the caveat that not all of Ripple's products are XRP-based.
The aggregate cryptocurrency market capitalization dropped by $15 billion over 24 hours Wednesday, according to CoinMarketCap.com.
As of 3:46 p.m. HK/SIN (2:46 a.m. ET Thursday), the total cryptocurrency market capitalization was at $186,275,052,509, according to Coinmarketcap.com — down more than 76 percent from its highs earlier in 2018.
— CNBC's Arjun Kharpal, Kate Rooney and Tyler Clifford contributed to this report.