The inquiry puts Cantor’s lucrative partnership with Tether under scrutiny. Cantor Fitzgerald acquired rights to a 5% stake in Tether in 2024 and reportedly custodies tens of billions of Tether’s US Treasury bill reserves. Blumenthal alleges that Cantor’s stake in Tether increased in estimated value from $600 million to $10 billion since Trump returned to office, and that Howard Lutnick received more than $250 million in that period, including a $192 million distribution from Cantor Fitzgerald.
The letter follows a report by the Democratic investigators on the Senate Permanent Subcommittee on Investigations last month alleging Tether’s USDt ($USDT) has become a key tool for Iran’s shadow banking network.
Blumenthal called on the US Treasury and Justice Department to investigate potential sanction violations. Tether responded with a statement saying it has been working with law enforcement for years and has frozen nearly $550 million in Iran-linked $USDT this year.
“Just as Tether has made untold millions in interest and investments from the stablecoins used in these illicit activities, so has Cantor Fitzgerald profited from its relationship with Tether,” Blumenthal wrote in his latest letter to Cantor.
Cointelegraph reached out to Cantor Fitzgerald and Tether but did not receive an immediate response.
Cantor-Tether ties date back to 2021
Cantor’s relationship with Tether began in 2021, when it started acting as a custodian for a portion of the US Treasuries backing the stablecoin issuer’s reserves.
Howard Lutnick oversaw Cantor as chairman and CEO during that period and helped negotiate its investment in Tether in April 2024.
Lutnick stepped down from Cantor after the Senate confirmed him as commerce secretary in February 2025. The firm then named his son Brandon chairman and his other son vice chairman.
Beyond earnings and compliance records, Blumenthal is seeking the terms of Howard Lutnick’s divestiture from Cantor and details of any other loan or financing Tether provided to Lutnick or his family to facilitate the transfer of ownership to his children.
The senator has also asked whether Cantor requires independent audits of Tether, whether it has ever reviewed terminating the partnership, and what steps it has taken to investigate allegations of illicit finance and sanctions evasion.
Blumenthal has asked Cantor to respond by Oct. 23.