What Is Tether (USDT)? The Stablecoin That Runs Crypto

Tether, traded under the ticker USDT, is the largest stablecoin in the world and one of the most important pieces of infrastructure in all of cryptocurrency. More USDT changes hands on a typical day than almost any other crypto asset. It is the default trading pair on most exchanges, the dominant dollar proxy in crypto markets, and a major holder of US Treasury bills.

It is also one of the most scrutinized and debated entities in the industry. This guide explains what Tether is, how it works, and the controversies that have followed it.

What Tether actually is

Tether is a stablecoin — a token designed to maintain a stable value of one US dollar per token. It is issued by Tether Limited, a company affiliated with the exchange Bitfinex. When someone deposits dollars with Tether, the company issues an equivalent amount of USDT. When someone redeems USDT, the company destroys the tokens and returns dollars.

The premise is simple: each USDT should be backed by one dollar (or one dollar's worth of equivalent reserves) held by Tether. This backing is what is supposed to keep the token reliably worth one dollar regardless of crypto market volatility.

USDT exists across many blockchains — Ethereum, Tron, Solana, and others — with the same one-dollar peg on each.

Why it matters so much

Tether is the lifeblood of crypto trading. Several factors make it central:

• It is the dominant trading pair. On most exchanges, the deepest liquidity is in USDT pairs rather than direct dollar pairs. Traders move in and out of positions through USDT.
• It enables dollar exposure without a bank. Users in countries with limited banking access or unstable currencies use USDT as a dollar proxy.
• It dominates on Tron and in emerging markets. USDT on the low-fee Tron network has become a major rail for remittances and payments in parts of the developing world.
• Its scale is enormous. Tether's reserves make it one of the larger holders of US Treasury bills globally — large enough to matter at a macroeconomic level.

How USDT maintains its peg

In normal conditions, USDT stays close to one dollar through arbitrage. If USDT trades below a dollar, arbitrageurs buy it cheap and redeem it with Tether for a full dollar, profiting from the difference and pushing the price back up. If it trades above a dollar, the reverse happens. The redemption mechanism is what anchors the peg — as long as the market believes redemptions will be honored.

The controversies

Tether has been dogged by questions for most of its existence. The major ones:

Reserve composition and transparency

For years, Tether faced criticism that it did not adequately prove its reserves actually backed the tokens in circulation. The company publishes attestations of its reserves, but critics long argued these fell short of a full audit. Over time Tether has shifted its reserves heavily toward US Treasury bills and increased its disclosures, addressing some concerns, though calls for a full audit by a major accounting firm have persisted.

Regulatory actions

Tether and Bitfinex settled with the New York Attorney General in 2021 over claims about the backing of USDT and the commingling of funds, paying a penalty without admitting wrongdoing. The CFTC also brought a related action. These settlements shaped much of the skepticism that follows the company.

The "what if it breaks" question

Because USDT is so central to crypto trading, a loss of confidence in its peg could cause severe disruption across the entire market. This systemic importance is itself a source of concern — Tether is, in a sense, too central to fail without consequences for everyone.

USDT vs USDC

The two largest stablecoins reflect different approaches. USDT (Tether) has the deepest liquidity, the widest exchange support, and dominance in emerging markets and on low-fee chains — but a longer history of transparency questions. USDC (Circle) markets itself on regulatory compliance and transparency, with monthly attestations and a US-regulated issuer, but has less liquidity in some markets and faced its own brief de-peg during the 2023 Silicon Valley Bank failure.

Neither is risk-free. Both are centralized stablecoins that depend on their issuers' solvency and the quality of their reserves. Our stablecoins guide covers the full landscape and the risks of each type.

The MiCA factor

The EU's MiCA regulation has reshaped the stablecoin landscape in Europe. Several major exchanges restricted or delisted USDT for EU customers ahead of full MiCA compliance, citing uncertainty over whether Tether would meet the new requirements, while USDC secured the necessary authorization. This regional divergence is part of an ongoing story — see our MiCA overview for the details.

How to think about holding USDT

For practical purposes:

• For trading, USDT's deep liquidity makes it convenient and often unavoidable.
• For holding meaningful value, consider the issuer risk and whether splitting across USDT and USDC reduces single-issuer exposure.
• For large amounts, remember that stablecoins are not bank deposits — they carry counterparty risk and are not government-insured.
• For yield, be especially cautious of platforms offering high returns on stablecoin deposits, which add platform risk on top of issuer risk.

The bottom line

Tether is simultaneously one of the most useful and most debated entities in cryptocurrency. It provides essential infrastructure — the dollar liquidity that crypto markets run on — at a scale that makes it systemically important. It has also operated under a persistent cloud of transparency and regulatory questions, some of which it has addressed over time and some of which remain open.

For most users, USDT is a practical tool to be used with awareness of its risks rather than blind trust. Understand that it is a centralized product with counterparty risk, not a literal dollar, and size your exposure accordingly.