The price of bitcoin, the most widely used virtual currency, has risen above US$10,000 for the first time, breaking a symbolic threshold in what has been a vertiginous ascent this year.
A general view of the Bitcoin booth at the 2015 International CES at the Las Vegas Convention Center.
The cost of buying one bitcoin as measured by the website coindesk.com was at US$10,673 by morning trading in Europe.
At the start of the year, it was valued at about US$1,000.
In his upcoming book "From bitcoin to reality blockchain", author Pascal Ordonneau called bitcoin's rise in value "a kind of explosion. The question is the duration of the explosion".
Virtual currencies have been the subject of much debate this year, with the CEO of JPMorgan Chase calling bitcoin a "fraud", but other executives saying it should not be dismissed.
Bitcoin and other virtual currencies were initially used primarily to buy illegal goods and services online.
In recent years, they have become a hot investment among speculators.