Tether (USDT): Born on Bitcoin's Blockchain, No Supply Cap, and a Freeze Switch

This method uses the Bitcoin blockchain, Proof of Reserves, and other audit methods to prove that issued tokens are fully backed and reserved at all times.

Tether wrote that sentence in June 2016, in a whitepaper titled Tether: Fiat currencies on the Bitcoin blockchain. The company had already been running for two years by then. Brock Pierce, Reeve Collins, and Craig Sellars founded it as Realcoin in July 2014; Sellars was also chief technology officer of the Mastercoin Foundation, which ran the Bitcoin-based token protocol later renamed Omni. Its first tokens went out under that name, minted as metadata written directly into Bitcoin’s own blockchain on October 6, 2014; the rename to Tether followed that November. Eleven years after those first tokens, on September 1, 2025, Tether stopped issuing and redeeming USDT on that same layer. It was born on Bitcoin’s ledger, and it left Bitcoin’s ledger.

What the whitepaper claims for itself

The document splits its own architecture into three layers, in its own words:

The first layer is the Bitcoin blockchain. The Tether transactional ledger is embedded in the Bitcoin blockchain as meta-data via the embedded consensus system, Omni.

The second layer was Omni, the protocol able to “grant (create) and revoke (destroy) digital tokens represented as meta-data embedded in the Bitcoin blockchain.” The third layer was Tether Limited itself, taking in and paying out fiat, issuing and retiring the matching tokens, and holding the reserves: on either side of the ledger, it decided whether a dollar became a token or a token became a dollar again. The whitepaper states the point of the whole arrangement directly:

Tether Limited is the only party who can issue tethers into circulation (create them) or take them out of circulation (destroy them). This is the main process by which the system solvency is maintained.

No cap sits anywhere in that description, and unlike every issuance schedule Bitcoin’s genealogy has argued over, none was ever proposed. Supply is not a formula; it is a mirror of whatever Tether Limited’s reserves hold on a given day, and both issuing and redeeming move only on that one company’s decision. The whitepaper does not dress this up as decentralization:

We recognize that our implementation isn’t perfectly decentralized since Tether Limited must act as a centralized custodian of reserve assets (albeit tethers in circulation exist as a decentralized digital currency).

It goes further, listing its own points of failure before anyone else could:

We could go bankrupt. Our bank could go insolvent. Our bank could freeze or confiscate the funds. We could abscond with the reserve funds.

The document named a fifth risk beside those four: concentrating all of it into a single point of failure. Five admitted weaknesses, published by the company admitting them, two years into its own operation. One would stop being hypothetical within three years.

Minting, redemption, and the migration off Bitcoin’s own ledger

Issuance and redemption pass through one company’s window, just as the whitepaper designed, but few holders ever stand at it. The company’s own fee schedule explains why: a direct request needs an approved account — approval sits at Tether’s “sole discretion” — a non-refundable $150 verification deposit, and a $100,000 minimum on either side, plus a 0.1% fee to acquire and the greater of $1,000 or 0.1% to redeem. Everyone under that bar buys and sells on an exchange instead, trading a supply that direct issuance and redemption have already set rather than touching the mechanism that sets it. Only the approved accounts that can put up $100,000, and Tether itself, can make the supply grow or shrink.

The ledger that mechanism runs on has also moved. USDT stayed exclusively on Bitcoin, via Omni, for barely three years: Tether issued its first Ethereum-based tokens in November 2017, and by May 2020 Ethereum held the largest share of Tether’s supply, with nearly 3.5 billion tokens issued there since that February, while Omni’s own supply had fallen by more than half in twelve months. Tether’s live transparency reporting puts total circulating USDT today at roughly $184 billion, third by market capitalization among all cryptocurrencies, issued natively across ten blockchains with bridged versions on several more. Tron and Ethereum between them now carry about 97% of it, each holding close to $89 billion — Tron alone just under half. Omni Layer, the chain the whitepaper was written about, carries none of it: Tether wound down new issuance and redemption there, alongside four other blockchains, on September 1, 2025.

The freeze function the whitepaper never mentioned

The 2016 whitepaper lists “our bank could freeze or confiscate the funds” as a risk Tether itself might suffer. It says nothing about Tether freezing anyone else’s funds, because at the time it couldn’t. Every USDT smart contract issued since carries three functions absent from the original design: addBlackList, which blocks an address from sending or receiving; removeBlackList, which reverses that; and destroyBlackFunds, which permanently burns whatever a blacklisted address was holding. A multisignature wallet inside Tether controls all three, and every call is a public, on-chain transaction — nothing about the freeze happens off the record.

The power gets used. In June 2025, Tether said the Department of Justice had acknowledged its help seizing $225 million in USDT tied to a pig-butchering romance-scam operation spanning several jurisdictions — one entry in what the company describes as more than $2.7 billion frozen or blocked in cooperation with over 255 law-enforcement agencies across 55-plus countries. In 2025 alone, one blockchain-security firm’s analysis counted $1.26 billion in USDT frozen across Ethereum and Tron, spread over more than 4,100 addresses, the majority of them on Tron and the larger average balances on Ethereum; just over half of that frozen total was burned outright rather than merely locked. A bitcoin sent to any address stays spendable by whoever holds the key, however that address later behaves. USDT carries no equivalent guarantee, and the whitepaper’s own silence on the point is the tell: the freeze switch was never part of the design it published.

Reserves: attestations, not audits

The whitepaper’s original promise was specific: “Professional auditors will regularly verify, sign, and publish our underlying bank balance and financial transfer statement.” What exists today is not that. Tether publishes a quarterly attestation from BDO Italia — a report confirming reserves matched a claimed figure at one moment — rather than an audit examining the controls behind that figure across a period. No Big Four firm has ever audited Tether’s books, and in April 2024 the chief executive gave the plainest explanation on record for why:

So you are a Big Four auditing firm, and you have the entire banking industry that is your customer. Why would you risk 100,000 customers for a couple of stablecoins?

The gap between attestation and audit stopped being theoretical once already. Between 2018 and 2019, Tether and Bitfinex — related companies under the same parent — lost access to $850 million held with a Panamanian payment processor, Crypto Capital. New York’s attorney general found the two companies moved reserve funds between each other to cover the shortfall without disclosing it to investors. The February 2021 settlement — $18.5 million paid, no admission of wrongdoing, quarterly reserve-composition reporting required for two years — closed with a statement from the attorney general naming exactly what the whitepaper had promised wouldn’t happen:

Tether’s claims that its virtual currency was fully backed by U.S. dollars at all times was a lie.

What Ardoino says about Bitcoin

Tether does not compete with Bitcoin; it holds it. In May 2023 the company announced it would regularly direct up to 15% of its net realized operating profits into Bitcoin purchases, adding the coins to its reserves while keeping them within what it calls its “Shareholder Capital Cushion.” By October 2024, Ardoino put the resulting stash at more than 82,000 BTC, worth roughly $5.8 billion at the time. A year later, he posted eight words:

Bitcoin and Gold will outlast any other currency.

A few months earlier, in July 2025, Tether had announced that it would end support for USDT on five legacy blockchains, one of them Omni Layer, the place USDT was first issued. The CEO gave the reason:

Sunsetting support for these legacy chains allows us to focus on platforms that offer greater scalability, developer activity, and community engagement — all key components for driving the next wave of stablecoin adoption.

The announcement granted that these networks “played a foundational role in Tether’s early growth” and named Layer 2 networks, Lightning Network first, among the places it was turning toward. The same year Tether left Bitcoin’s own settlement layer as a place to mint tokens, it kept adding to a Bitcoin position it does not need to run USDT at all. One company, walking away from Bitcoin’s base layer as an issuance venue while walking back onto a payment layer built on it, and deeper into Bitcoin itself as a thing to own.

Significance to Bitcoin

USDT tests what Bitcoin’s design refuses to allow: a single company deciding how much money exists and who may move it. The six structural features behind Bitcoin’s claim to being digital gold rest on there being no such company — no issuer whose reserves set the supply, no administrator able to add an address to a blacklist. USDT inverts nearly the whole list at once: a named issuer, a supply that moves at that issuer’s discretion, and a freeze function exercised in full public view on the very ledger transparency is supposed to guarantee. USDC shares the same structure: its supply, too, is set by an issuer. The twelve-chain design comparison sets both alongside the rest of the field.

What separates the two stablecoins is not the structure; it is how much of it each issuer shows. Jeremy Allaire’s Circle discloses USDC’s reserve composition itself, and put its own 2023 de-peg on the public record, when deposits stuck at Silicon Valley Bank briefly pushed USDC off its dollar. What Tether has shown is a quarterly attestation, a narrower window than an audit, and its own chief executive has explained on the record why the firms best positioned to look more closely choose not to. That explanation is the evidence that the narrow window is not an accident.

Bitcoin’s ledger is where USDT was born and where USDT officially left. Tether has put distance between itself and Bitcoin’s base layer without loosening its hold on bitcoin as an asset, and eleven years of USDT’s record show that the two moves do not contradict each other at all.