According to CoinWorld, Richard Blumenthal, the top-ranking Democrat on the U.S. Senate Permanent Subcommittee on Investigations, sent letters to Tether and Nxum Group seeking details about arrangements related to payments Tether made to Nxum Group. Nxum Group was co-founded by White House crypto adviser Bo Hines and received large payments from Tether while Hines was serving as a White House crypto adviser. Blumenthal said the business relationships among Tether, Nxum Group, and Bo Hines raise ethical and legal concerns.