While quite a few Bitcoin millionaires have been minted since the cryptocurrency's rise, the world's first Bitcoin billionaires arrived this December: the Winklevoss twins.

That's right: the duo that first gained public recognition for claiming that Mark Zuckerberg stole the idea of Facebook (FB  ) from them are now amongst the highest Bitcoin earners. After the Winklevosses sued Zuckerberg, they reached a settlement of $65 million - $11 million of which they invested into Bitcoin in March 2013.

The twins bet on Bitcoin when each coin was worth only $120. From these small beginnings, Bitcoin has since skyrocketed to over $11,000 in the past week, capping a boom that began in 2016 but has only accelerated in the latter half of 2017. In spite of all the talk about how Bitcoin threatened to global financial stability, and had great potential for criminal exploitation, Bitcoin's rise has made fortunes for many of its early backers.

The Winklevoss's Bitcoin hoard is estimated to be approximately 100,000 Bitcoins. The twins have restyled themselves since their Facebook drama, switching their image from would-be tech entrepreneurs to Bitcoin entrepreneurs. They currently own their own online exchange and venture capital fund, with plans to launch an exchange-traded fund in New York. They still lack approval from financial regulators, but according to Cameron Winklevoss, the duo are "in it for the long haul" and do not plan on selling a single Bitcoin until the time is right.

The Winklevoss twins are part of a very select group of people with Bitcoin holdings exceeding $1 billion. Others in this group include the cryptocurrency's inventor, the anonymous man or group with the pseudonym Satoshi Nakamoto.

One of the unique features of the cryptocurrency is its lack of backing from a central bank, deriving its value from the network of users. In spite of its unusual orientation, Bitcoin reached an all-time high in the last week of November 2017, even after Goldman Sachs CEO (GS  ) Lloyd Blankfein and JPMorgan Chase CEO (JPM  ) Jamie Dimon voiced their opinion that Bitcoin was a fraud. The Federal Reserve has also warned that Bitcoin may be bad for national financial stability, if it becomes more widespread and gains dominance in the realm of currencies.

In spite of all the doubt, in the last week of November, the Chicago Mercantile Exchange won approval to launch Bitcoin futures trading and has even activated plans to offer contracts in late December 2017. For many, the approval of the Chicago Mercantile Exchange is tantamount to a stamp of legitimacy, which may increase the rising wave of institutional interest in Bitcoin, while also increasing the price.

In spite of all the attention it has been getting in recent years, the cryptocurrency remains mostly unregulated. The next step for the government remains bringing virtual currency exchanges into money-laundering regulation via amendments to the E.U. legislation in the next weeks.