Tyler and Cameron Winklevoss, who became household names a decade ago when they sued Facebook CEO Marc Zuckerberg for allegedly stealing their idea for the social media platform, have now become billionaires.

WINKLEVOSS TWINS FIRST BITCOIN BILLIONAIRES

The twins bought 100,000 bitcoins when they first emerged in 2013 at $1,000 each. The value of bitcoins has increased significantly, and recently began trading at $11,310. The Winklevoss’ investment four years ago has brought them up to over one billion dollars.

The brothers are among the digital currency’s most vocal proponents, and launched the Gemini exchange in 2016, on which people could buy and sell their bitcoin. Coinbase, however, is the largest exchange. When bitcoin topped $11,000 on Nov. 29, users had difficulty signing onto either system.

Bitcoin, however, has many critics that believe that the market is bound to pop, considering the more than 1,300 other cryptocurrencies out there. Still, they agree that the Winklevosses deserve some credit for sticking with the currency despite its ups and downs. Some, however, disagree that they are first ‘bitcoin billionaires.’

“The Winklevoss twins are not the first bitcoin billionaires, but simply the ones with the biggest PR and media outreach, which cements their position as forward-thinking pioneers, and as a result, it will definitely encourage more people to buy bitcoin,” said Angel Versetti, co-founder and CEO of Ambrosus, according to CBS News.

The growth of bitcoin, though, is still unprecedented and impressive, with a market capitalization of more than $191 billion. For comparison, the value of McDonalds is now $138 billion, Morgan Stanley is at $95 billion, and Target is $34 billion.