The latest to voice his scepticism of cryptocurrency is Microsoft founder Bill Gates who on Monday said that investing in digital assets is \u201cgreater fool theory\u201d and he would short Bitcoin if he could. "As an asset class, you're not producing anything and so you shouldn't expect it to go up. It's kind of a pure 'greater fool theory' type of investment," Bill Gates told CNBC on Monday. "I agree I would short it if there was an easy way to do it," he added. Bill Gates along with fellow billionaires Warren Buffett and Charlie Munger were participating in a conversation on CNBC on a variety of topics on Monday. Not easy to short It should be noted here that shorting cryptocurrencies is not easy. Even though a few exchanges such CME and Cboe have made available to sell, or short, bitcoin futures, it\u2019s not easy to make bets against virtual currencies in comparison to more established assets like corporate shares. Bill Gates in the month of February had said that digital currencies encouraged illegal behavior. \u201cRight now crypto currencies are used for buying fentanyl and other drugs so it is a rare technology that has caused deaths in a fairly direct way,\u201d he said. Just days back during annual general meeting of Berkshire Hathaway\u2019s with its shareholders, Warren Buffett had said that \u00a0bitcoin is \u201cprobably rat poison squared.\u201d The company\u2019s vice chairman Charlie Munger had said that \u201csomebody else trading is turds and you decide I can\u2019t be left out.\u201d The Bitcoin price briefly surged to above $19,000 in mid-December last year. However, the popular digital currency has since then lost over half its value and was trading near $9,300 on Monday morning. Bitcoin has lost a sizable chunk of its value since this year has started amid reports of increasing crackdown in different parts of the world.