https://www.reuters.com/article/us-usa-cftc-bitcoin/u-s-derivatives-regulator-files-suits-against-three-virtual-currency-operators-idUSKBN1F81K9 >The U.S. derivatives watchdog said on Friday that it has filed charges against three separate virtual currency operators alleging the defendants had defrauded customers and broken other commodity trading rules, in a further sign regulators globally are cracking down on the emerging asset class.