Now, Genesis Mining, a cryptocurrency mining company based in Iceland, is trolling Buffett. The company has erected billboards outside of the Omaha offices of Berkshire Hathaway. The billboards say: At the annual shareholder meeting of Berkshire Hathaway earlier this month, Buffett said that Bitcoin was “probably rat poison squared.” He advised his investors to avoid it and other cryptocurrencies. Bitcoin and other cryptocurrencies have lost a lot of value this year. Last year, Bitcoin and its competitors seemed unstoppable as the valuation of cryptocurrencies were steadily on the rise. Bitcoin has declined by 40% since the beginning of this year.