https://phys.org/news/2018-06-bitcoin-month-currency-exchange-theft.html > The decline also follows a Wall Street Journal report that U.S. regulators have asked virtual currency exchanges to provide trading data to aid an investigation into virtual currency manipulation. The reports raised concerns about the future of virtual currency markets. > David Jones, Capital.com's chief market strategist, says Bitcoin is "a classic case of an economic bubble." Last year, the virtual currency increased sixfold and hit a record high of $19,783 in December. Explore further: Federal regulator gives OK for bitcoin futures to trade