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(USDT) is the single most-used stablecoin in crypto — the plumbing that most of the world's crypto trading runs on. It is also the most controversial. Understanding the Tether story means understanding the difference between “backed 1:1 by dollars” and “we promise we have the money” — and why that distinction has kept regulators, journalists, and traders arguing for a decade.
The pitch: money that doesn't move
The original idea behind Tether was simple and genuinely useful. Crypto exchanges — especially those outside US jurisdiction — needed a way to let customers move in and out of “dollars” without actually holding US dollars in a bank. US banking is slow, expensive, and legally risky for crypto companies. A token that was always worth one dollar and could move on a blockchain would solve that problem.
USDT launched in 2014 on the Bitcoin blockchain's Omni Layer, then expanded to Ethereum, Tron, Solana, and many other chains. The pitch was: for every 1 USDT in circulation, Tether Limited held 1 US dollar in a bank account. You could always redeem USDT for dollars (if you were an approved customer), and you could always sell it on an exchange for roughly $1 because the market trusted the peg.
This worked. USDT became the de facto trading pair for crypto worldwide. By 2024 its market cap exceeded $100 billion, dwarfing every other stablecoin. But the very thing that made it useful — its ubiquity — also made the question of what was actually behind it incredibly important.
The reserve question
From the beginning, Tether promised “full transparency” and a professional audit. For years, neither materialized. Instead, Tether released periodic “attestations” — not full audits by a Big Four accounting firm, but reports from the accounting firm BDO Italia (which took over from the Cayman Islands firm Moore Cayman) stating that, at a specific moment in time, Tether's consolidated assets exceeded its consolidated liabilities.
The distinction matters. An attestation says “we looked at the books on this date and the numbers matched.” An audit says “we examined the accounting system, verified the valuation methodology, tested internal controls, and believe the financial statements are fairly presented.” Tether has never produced a full audit.
What the attestations did reveal, especially after the 2021 NYAG settlement, was that Tether's reserves were not just US dollars in a bank. They included commercial paper, fiduciary deposits, loans to affiliated companies, precious metals, and — later — Bitcoin and US Treasury bills. Tether argued this was prudent diversification. Critics argued it was risk-taking with funds that customers believed were sitting in cash.
A stablecoin issuer is effectively an unregulated money-market fund. It takes in dollars, invests them, and pays out tokens that are redeemable for dollars. The profit comes from the yield on the reserves. The risk is that the reserves lose value (defaults, illiquidity, market crash) while the obligation (1 USDT = $1) stays fixed. If enough people redeem at once and the reserves can't be liquidated at par, the peg breaks. This is a bank run, in substance, even if it looks like a crypto thing.
The regulatory reckoning
In 2019, the New York Attorney General alleged that Tether and Bitfinex (its affiliated exchange) had used Tether's reserves to cover an $850 million loss at Bitfinex — meaning the reserves were not fully available to back USDT. The companies fought the investigation but ultimately settled in February 2021 for $18.5 million, admitting no wrongdoing but agreeing to publish quarterly reserve reports.
Later that year, the CFTC fined Tether $41 million for making misleading statements about being 100% backed by fiat currency. The CFTC found that from 2016 to 2018, Tether had unencumbered reserves matching the outstanding USDT supply on only 27.6% of days in that period. On the other days, reserves included loans to Bitfinex and other non-cash assets.
Tether's response was essentially: “We never said every dollar was in a single bank account. The reserves are real, and we have honoured every redemption.” Both things can be true: the reserves may be sufficient in aggregate, and the original “100% backed by fiat currency” language may have been misleading about what “backed” actually meant.
The stress tests: FTX and SVB
Theory is one thing; a bank run is another. In November 2022, when collapsed, panic swept through stablecoins. Tether faced the opposite problem: everyone wanted their dollars now.
Tether processed about $3 billion in redemptions in the days following the FTX collapse, and its price slipped only briefly, by a few cents. It had already survived a larger run: after TerraUSD collapsed in May 2022, holders redeemed over $10 billion in two weeks — roughly 13% of Tether's supply — while USDT dipped as low as $0.95 before recovering. That was the largest real-world stress test Tether has faced, and it passed. Critics noted that the redemptions were processed for institutional clients (not retail, who had to sell on exchanges), and that the speed of redemption proved the reserves were liquid enough — at least for this scale of run.
The next test came in March 2023, when the failure of Silicon Valley Bank briefly de-pegged USDC — Circle had $3.3 billion exposed to SVB. Tether again faced a wave of redemptions and reported processing another $1.6 billion within days while keeping its peg.
Whether Tether could survive a much larger run — say, 40% of supply in a week, with a concurrent crypto market crash that cratered the value of its Bitcoin and corporate bond holdings — remains an open question. The 2022 test was severe but not worst-case.
The pivot to T-bills
After the regulatory settlements and the 2022 stress tests, Tether significantly shifted its reserve composition. By 2024, attestations showed the majority of reserves in US Treasury bills and money market funds, with smaller allocations to Bitcoin, gold, and secured loans. Commercial paper — once a major component and a source of criticism (whose paper? what rating?) — was eliminated entirely.
This shift addressed the most concrete criticism: that Tether's reserves were opaque and potentially illiquid. T-bills are the most liquid and safest dollar asset in the world. If most of the reserves are in T-bills, the “can they actually pay?” question is much easier to answer affirmatively — even without a full audit.
The timeline
Tap any event to expand its story.
Tether Limited (originally "Realcoin") is announced by Brock Pierce, Reeve Collins, and Craig Sellars. The premise is simple: issue a token on the Bitcoin blockchain (via the Omni Layer) that is backed 1:1 by US dollars in a bank account. It is rebranded to "Tether" within months.
Tether begins trading on Bitfinex, an exchange that shares executives and ownership with Tether Limited. The close relationship between the exchange and the stablecoin issuer would become a central point of controversy.
As the crypto bull market intensifies, USDT supply surges from ~$10M to over $1 billion. It becomes the de facto trading pair for almost every exchange that cannot easily use US banking. Tether moves to Ethereum (ERC-20), dramatically improving usability.
After years of promising a full audit, Tether releases a memorandum from a law firm (not an accounting firm) stating that Tether held approximately the right amount of dollars. A full audit by a reputable accounting firm is never produced — and still has not been, as of this writing.
The New York Attorney General's office initiates an investigation under the Martin Act, alleging that Tether and Bitfinex covered up an $850 million loss of commingled client and corporate funds. Tether attempts to block the investigation but fails in court.
Tether and Bitfinex settle with the NYAG for $18.5 million, admitting no wrongdoing but agreeing to provide quarterly reports on Tether's reserves for two years. The settlement reveals that Tether's reserves were not purely US dollars — they included commercial paper, fiduciary deposits, and other assets.
The Commodity Futures Trading Commission fines Tether $41 million for making misleading statements about being 100% backed by fiat currency. The CFTC finds that from 2016 to 2018, Tether held sufficient reserves on only 27.6% of days.
When TerraUSD collapses in May 2022, panic spreads to stablecoins. Tether processes over $10 billion in redemptions in two weeks — roughly 13% of its supply — and recovers from a brief dip to about $0.95. It is the largest real-world stress test Tether has faced. In November, FTX's collapse brings a smaller wave, about $3 billion in a few days, and the peg holds again.
Tether publishes attestations showing its reserves are increasingly held in US Treasury bills and money market funds, moving away from commercial paper. By 2024, Tether reports holding the majority of its reserves in T-bills, with significant Bitcoin and gold positions as well.
Despite years of skepticism, regulatory action, and competition from more transparent stablecoins, USDT remains the largest stablecoin by market cap, the dominant trading pair globally, and the primary settlement asset for crypto markets outside the US.
Why it's still #1
Despite everything — the missing audit, the regulatory fines, the NYAG settlement, a decade of skepticism — USDT remains dominant. Why?
- Network effects. USDT is the trading pair on almost every non-US exchange. If you want to trade crypto and you're not using US banking, USDT is the default. Liquidity begets liquidity.
- Regulatory arbitrage. USDC (Circle) and other US-regulated stablecoins have become more cautious about who they serve, delisting jurisdictions and freezing tokens for compliance. USDT fills the gap — especially in emerging markets and non-US-facing exchanges.
- It works. Through multiple crises, Tether has honoured redemptions and maintained the peg. A decade of “it's going to zero” predictions that didn't come true has, fairly or not, built a kind of grudging trust.
- Yield. Tether earns interest on its reserves (T-bill yields on a reserve that passed $100 billion in 2024 is significant revenue) and shares some of that yield with exchanges and large holders, creating an incentive to keep using it.
Tether is not a scam in the sense of “there is no money.” The attestations, the 2022 stress tests, and the pivot to T-bills all suggest the reserves are real and largely liquid. But it is also not what the original marketing implied — a simple 1:1 dollar bank account. It is a complex, partially opaque financial institution holding $100+ billion in assets against $100+ billion in tokenized liabilities, run by a private company with a history of misleading statements. The risk is not zero. The risk is that, in a sufficiently extreme scenario, the reserves (some of which are volatile or illiquid) cannot be liquidated fast enough at par to meet redemptions. That risk has decreased as reserves shifted to T-bills, but it has not disappeared. Treat USDT as you would any uninsured bank deposit: convenient, usually safe, but not guaranteed.
Key takeaways
- Tether (USDT) is the largest stablecoin in the world, and the de facto trading pair for crypto outside the US. Its dominance is a network effect, not a vote of confidence.
- Tether has never produced a full audit. After regulatory settlements (NYAG $18.5M, CFTC $41M), it began publishing quarterly attestations showing reserves exceeding liabilities — but these are not audits.
- Tether survived its largest stress test (after Terra's collapse in May 2022, $10B+ in redemptions in two weeks) and a smaller one after FTX, recovering its peg each time. It later shifted reserves to mostly US Treasury bills, addressing the most concrete criticism.
- The core risk — that reserves might not be liquid at par in an extreme run — has decreased but not vanished. USDT is convenient and usually safe, but it is not insured and not guaranteed.
- For more on how stablecoins compare, see the Stablecoin Wars deep dive. For the most spectacular stablecoin failure, see Terra/Luna.