Cantor Fitzgerald Tether Letter: Who Holds the USDT Reserves?

On 8 October 2026, Senator Richard Blumenthal sent a letter to the Wall Street firm Cantor Fitzgerald asking about its business with Tether, the company behind the stablecoin USDT. The letter says: “While Tether claims to operate out of El Salvador, the vast majority of its assets reside in the United States under your custodianship.” It asks for answers by 23 October 2026.

For anyone holding USDT, the useful part isn’t the politics. It’s the question underneath: who holds the money behind a stablecoin, and how would you know? A letter like this asks questions. It doesn’t prove anything about a company, and neither do we.

What is the Blumenthal letter to Cantor Fitzgerald?

It is a request for information, not a legal order. Senator Blumenthal is the ranking member, meaning the top Democrat, on the Senate’s Permanent Subcommittee on Investigations. His office put out a press release on 8 October with the letter attached.

The letter says: “I am writing to request information about your business partnership with Tether.” A request asks a company to answer questions and share records. A subpoena is a legal order, and the word does not appear in the letter. The letter makes 13 numbered requests and asks Cantor to preserve all documents and records tied to its Tether relationship.

Who are Tether and Cantor Fitzgerald?

Tether issues USDT, a stablecoin, which is a token designed to track the U.S. dollar. The idea is that for each token in circulation, Tether holds assets in reserve. That reserve is the backing.

Cantor Fitzgerald is a Wall Street financial services firm. CoinDesk’s report on the letter puts the link plainly: “Cantor holds and manages Tether’s reserves in the U.S.” The letter is addressed to Brandon Lutnick, Cantor’s chairman. CoinDesk identifies him as the son of U.S. Commerce Secretary Howard Lutnick, who, The Block notes, led Cantor before joining the administration.

The letter also says Cantor’s 5% stake in Tether “has increased in value from $600 million to an estimated $10 billion.” That is the senator’s estimate, and we have not seen another source check it. So, per the letter, there are two ties: Cantor holds assets for Tether, and Cantor owns part of Tether.

Where does the USDT backing sit?

According to the Senate documents, mostly with one firm. A custodian is a firm that holds assets for someone else for safekeeping. A Senate minority staff report from 28 September says “Tether’s primary custodial relationship for its treasuries runs through Cantor Fitzgerald,” and describes Tether’s reserves as “held overwhelmingly in U.S. Treasury bills.” A Treasury bill is a short-term loan to the U.S. government, repaid on a set date.

Tether’s own account is a little different in form. Its Q2 2026 report, checked by the accounting firm BDO as of 30 June, says “the majority of reserves remain in U.S. government-backed instruments and short-term liquidity facilities,” with about $184.6 billion in tokens issued. That post doesn’t name a custodian at all. An attestation like this is a dated snapshot of the numbers on one day, which is narrower than a full audit.

What does the Senate report behind the letter allege?

The 28 September report, titled “Tethered to Terrorism: Crypto and Iran’s Shadow Banking Network,” alleges that “Tether has become a primary illicit international payment system for Iran” and that it “repeatedly failed to block wallets associated with Iranian exchanges.” A minority staff report comes from the party that isn’t in charge of the committee, so it is one side’s findings, not a ruling. The report says Tether had not responded by the time it was published.

The same day, Tether posted that it had helped freeze about $550 million in Iran-linked USDT in 2026 alone. The Block quoted Tether CEO Paolo Ardoino: “Tether can act when credible information is provided by law enforcement.” Freezes like these are the same issuer power at the center of the Conduit lawsuit against Tether.

What does the letter ask Cantor?

Four of the 13 requests stand out for a holder:

• Whether Cantor requires “regular audits of Tether and its operations from a credible independent auditor.”
• A description of “Cantor Fitzgerald’s custodial relationship with Tether” and related records.
• How Cantor monitors Tether’s compliance with sanctions and anti-money-laundering rules.
• Under what circumstances Cantor would end the relationship.

Those are close to the questions any holder could ask about the money behind a stablecoin. CoinDesk reported that neither Cantor nor Tether immediately responded to requests for comment. In the press release, the senator says the arrangements come “at the expense of America’s national security.” That is his view, not a finding.

What does this mean for your money?

Three points, none of them a signal to buy, sell or switch anything:

1. A stablecoin is a chain. You hold the token, Tether issues it, and, per the Senate documents, a separate firm holds a large share of what backs it. Each link is a company with its own rules and risks.
2. Concentration is worth knowing. When “the vast majority” of the backing sits with one firm, what happens at that firm, including questions from Congress, deserves a holder’s attention. That isn’t a claim that anything is wrong there.
3. A letter is a question, not a verdict. Treating allegations as facts is a mistake, and so is dismissing them, until the answers are in.

We looked at how dollar stablecoins and Treasury bills connect in GENIUS Act Stablecoins and who keeps the interest in Stablecoin Interest Ban.

A four-question backing check for any stablecoin

Here is a tool you can run on any stablecoin you hold, with USDT filled in as of 14 October 2026:

Question	USDT	A made-up coin picked from an app
Who issues it?	Tether	“A team online”
What backs it, as of when?	Mainly U.S. government-backed instruments, per Tether’s 30 June report	Unknown
Who holds the backing, and how many firms?	Cantor Fitzgerald for the vast majority, per the senator’s letter; not named by Tether	Unknown
Who is asking questions, and when are answers due?	A Senate letter, answers due 23 October 2026	None tracked

Four blanks on the right-hand side tell you more than any headline. The issuer is the quickest one to fill in.

What to watch next, and what would change this view

1. The 23 October deadline, and whether Cantor’s answers are made public.
2. Any public reply from Cantor or Tether.
3. Tether’s next quarterly report, and whether it names who holds its reserves.
4. Whether the subcommittee holds a hearing or publishes a follow-up after the deadline.

If records show the backing is spread across many custodians, the concentration point gets weaker. If Cantor’s answers settle the senator’s questions, the open-questions point changes. If Tether starts naming its custodians, the information gap closes. In each case, the dated document beats any summary, including this one.