https://www.reuters.com/article/us-usa-fed-powell-libra/fed-chief-calls-for-facebook-to-halt-libra-project-until-concerns-addressed-idUSKCN1U51VE >U.S. Federal Reserve Chairman Jerome Powell said on Wednesday that Facebook's plan to build a digital currency called Libra "cannot go forward" until serious concerns are addressed, comments that pressured the project and dented the price of the original cryptocurrency bitcoin.