Central Banks are generally wary of giving up their hold over their respective currencies and hence are reluctant to approve/regularise the currency within their jurisdiction. The warnings by ECB and US Fed officials about crypto assets mention that these are no real investment and being highly volatile and that as these pose risks to financial stability, greater regulations may be warranted. The US Treasury Department, meanwhile, flagged its concerns that wealthy individuals could use the largely unregulated sector to avoid tax and said it wanted big crypto-asset transfers reported to authorities.