Tether is facing renewed scrutiny on Capitol Hill over millions of dollars that reportedly flowed to a consulting firm co-owned by Bo Hines while he helped shape U.S. stablecoin law at the White House.

Sen. Richard Blumenthal, D-Conn., the top Democrat on the Senate Permanent Subcommittee on Investigations, sent a letter to Tether CEO Paolo Ardoino on Thursday demanding records of the company's dealings with Hines and Nxum, the consulting firm he co-founded. Blumenthal gave the stablecoin issuer until. 3 to respond.

Hines served as executive director of President Donald Trump's Presidential Council of Advisers for Digital Assets and was a key architect of the GENIUS Act, the federal framework for payment stablecoins signed into law in July 2025. He left the White House on Aug. 9, 2025, and Tether named him CEO of its new U.S. division the following month. The deal now under examination was struck two months before the GENIUS Act became law.

Blumenthal's letter builds on an Oct. 14 Wall Street Journal investigation, which reported that Nxum has earned $6.3 million from a deal Tether struck in May 2025. Under the arrangement, Tether agreed to pay a marketing firm called Notorious $415,000 a month, and the firm passed most of the first payment to a wallet used by Nxum, where it was split three ways. Later payments went directly to Nxum after Hines had left government. According to the Journal, Hines retained his one-third stake in Nxum throughout his White House tenure.

The Journal also reported that Hines urged lawmakers to double the legislation's compliance window from 18 to 36 months, a change that chiefly benefited Tether, the issuer of USDT, the world's largest stablecoin. USDT's scale puts Tether at the center of the market the GENIUS Act now governs, making the company a focal point for congressional oversight of the new framework. Messages reviewed by the newspaper showed Hines sharing talking points about Republican holdouts with his Nxum partners. After a call from Ardoino, Hines' father and Nxum co-owner, Todd Hines, wrote: “They want us to obliterate these members that are fighting crypto.”

A Nxum representative told the Journal that Hines was not involved in the Tether deal while in government and “did not receive any Tether-derived funds during that period.”

“Tether is aware of the allegations reported in The Wall Street Journal that form the basis of Senator Blumenthal's letter,” the company said in a statement. “External counsel previously conducted an in-depth internal investigation into the matter, which found no evidence of wrongdoing.”

In his letter, Blumenthal wrote that the payment structure suggests Tether “was likely well aware of the illegality and impropriety” of paying a sitting official, and that the arrangement “implicates federal ethics, anticorruption, and lobbying laws.” He also asked about a Nxum pitch deck, reported by the Journal, which said Tether would buy a 25% stake in the firm for $56 million.

It is Blumenthal's second Tether-linked letter this month. On Oct. 8, he requested records from Cantor Fitzgerald, Tether's reserve custodian and a 5% shareholder chaired by Commerce Secretary Howard Lutnick's son, about that relationship.

That request followed a report from Blumenthal's staff finding that most Iran-linked wallets used USDT. Tether responded by citing roughly $550 million in Iran-linked freezes, including $344 million in April. Lutnick defended Tether at his confirmation hearing last year, and Sens. Elizabeth Warren and Ron Wyden pressed him in April over a reported Tether loan to a trust for his children. With Tether due to respond by Nov. 3, the letter sets the next checkpoint in an oversight push that now spans the issuer itself, its reserve custodian, and the prevalence of USDT in Iran-linked wallets.