Sen. Richard Blumenthal has opened an investigation into reported payments of about $6.3m (£4.7m) from stablecoin issuer Tether to Nxum, a consulting company co-founded by former White House cryptocurrency adviser Bo Hines.
The Democratic senator from Connecticut said the arrangement raised potential conflicts of interest and questions about whether federal ethics and lobbying laws had been breached.
In a letter to Tether chief executive Paolo Ardoino dated 22 October, Blumenthal requested records concerning the company’s relationship with Nxum. His inquiry followed a Wall Street Journal investigation into the payments made while Hines was involved in shaping cryptocurrency policy for President Donald Trump.
The Journal reported that Tether agreed in May 2025 to pay Nxum $415,000 per month for strategic communications, lobbying and public relations work. Hines retained a one-third ownership stake in Nxum while serving as executive director of the White House Council of Advisers for Digital Assets.
Blumenthal alleged that Hines communicated with Nxum through encrypted messaging applications while supporting provisions in the GENIUS Act, the major stablecoin legislation signed into law in July 2025.
The provisions reportedly allowed more time to meet compliance requirements and gave foreign stablecoin issuers, including Tether, greater flexibility to continue operating in the United States.
The senator also sought an explanation for the way the payments were made. Tether allegedly did not contract directly with Nxum, instead sending cryptocurrency through another marketing company, Notorious. The funds were then distributed to Nxum’s owners.
After Hines left the White House in August 2025, Tether began working directly with Nxum and later hired Hines to lead its newly created US operations.
“The highly unusual terms and nature of Tether’s business relationship with both Nxum and Bo Hines raise alarming ethical and legal concerns,” Blumenthal wrote.
Representatives for Hines told the Journal that he did not know about or take part in the Tether agreement while he was serving in government. Blumenthal also referred to reports that Nxum had sought further investment by claiming Tether planned to buy a 25% stake in the company for $56m.
The senator has asked for contracts, cryptocurrency transaction records, wallet addresses and communications involving Tether, Nxum, Notorious and Hines. He sent a separate request for similar material to Nxum chief executive Todd Hines, Bo Hines’ father.
Tether and Nxum have until 6 November to respond.
The inquiry is part of Blumenthal’s wider examination of Tether and its political links. Earlier this month, he requested information from Cantor Fitzgerald about its financial relationship with Tether after a congressional report alleged that Tether’s USDT stablecoin was being used in transactions connected to Iran’s shadow banking network.
Cantor Fitzgerald, formerly led by Commerce Secretary Howard Lutnick and now controlled by his sons, owns a minority stake in Tether and manages substantial assets backing USDT.
Blumenthal’s latest investigation will examine whether Tether’s financial dealings with politically connected figures improperly affected federal cryptocurrency legislation. No wrongdoing has been established, and Tether has not publicly commented on the investigation.
