Senator Richard Blumenthal has given Cantor Fitzgerald until Oct. 23 to hand over records on its Tether partnership, including the more than $250 million that Commerce Secretary Howard Lutnick and his family received from the arrangement since President Trump returned to office.

Blumenthal, the ranking Democrat on the Senate Permanent Subcommittee on Investigations, sent the letter on Thursday to Brandon Lutnick, who became chairman of the investment bank after his father left to lead the Commerce Department. The inquiry targets Cantor's 5% stake in Tether, acquired in 2024, and the bank's role as custodian for a portion of the stablecoin issuer's US Treasury bill reserves.

What is Blumenthal alleging?

In the letter, Blumenthal claims Cantor's stake in Tether grew from an estimated $600 million to $10 billion in value during the period Howard Lutnick collected payouts. Those include a $192 million distribution from Cantor Fitzgerald, according to the senator's account.

"Disturbingly, Cantor Fitzgerald's lucrative business arrangements with Tether come at the expense of America's national security," Blumenthal wrote. He added: "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."

The letter follows a Democratic staff report last month from the Permanent Subcommittee on Investigations alleging that Tether's USDT has become a primary vehicle in Iran's shadow banking network. Blumenthal is now calling on the Treasury Department and the Department of Justice to examine potential sanctions violations.

What records is the senator demanding?

Blumenthal's document request spans compliance, communications and compensation. The senator is seeking:

• Earnings and compliance records related to Cantor's Tether work
• All communications involving Howard Lutnick concerning Tether, including after his departure from the bank
• Terms of Howard Lutnick's divestiture from Cantor and any loans or financing Tether extended to Lutnick or his family to facilitate the transfer of ownership to his children
• Documentation on whether Cantor requires independent audits of Tether
• Records of any internal review of whether to terminate the partnership
• Steps taken to investigate allegations of illicit finance and sanctions evasion

How did Tether respond?

Tether issued a statement saying it has worked with law enforcement for years and has frozen nearly $550 million in Iran-linked USDT this year. The company framed the Iran allegation as a mischaracterization of its cooperation record.

Cointelegraph reached out to Cantor Fitzgerald and Tether but did not receive a response to the latest letter. The Subcommittee's Oct. 23 deadline gives Cantor roughly six weeks to compile the materials.

How did the Cantor–Tether relationship take shape?

The relationship dates to 2021, when Cantor began custodying a portion of the US Treasuries backing Tether's reserves. Howard Lutnick, then Cantor's chairman and CEO, helped negotiate the April 2024 investment that gave the bank rights to a 5% Tether stake.

The Senate confirmed Howard Lutnick as Commerce Secretary in February 2025. Cantor then named his son Brandon chairman and his other son vice chairman. The transition has put the Lutnick family's accumulated Tether-linked proceeds under direct congressional scrutiny for the first time.

What enforcement window now opens?

Blumenthal's referral to Treasury and Justice creates a parallel track to the document request. If federal investigators find that Tether's rails processed transactions for sanctioned Iranian entities, enforcement actions could target both the stablecoin issuer and its financial intermediaries — a category Cantor now occupies by virtue of its custody mandate and equity stake. The Oct. 23 deadline will test whether Cantor produces the records voluntarily or contests the subpoena path, a procedural fork that will determine whether the inquiry moves into a formal enforcement phase or stalls in negotiation.