What Is USDT (Tether)?
A comprehensive guide to the world's largest stablecoin by market capitalization.
What Is a Stablecoin?
A stablecoin is a cryptocurrency designed to maintain a fixed value relative to a reference asset — most commonly the US dollar. Unlike Bitcoin or Ethereum, whose prices fluctuate by the minute, stablecoins aim to stay at exactly $1.00 per token. They serve as a bridge between traditional finance and the crypto ecosystem, letting users hold, send, and receive dollar-equivalent value on blockchain networks without needing a bank account.
USDT: Origins and Issuer
USDT — commonly known as Tether — is issued by Tether Operations Limited, a company incorporated in the British Virgin Islands. It was originally launched in October 2014 on Bitcoin's Omni Layer protocol under the name "Realcoin" before rebranding to Tether. The project was co-founded by Brock Pierce, Reeve Collins, and Craig Sellars. Tether Operations is affiliated with the iFinex group, which also operates the Bitfinex exchange.
The core idea behind USDT is simple: for every token in circulation, Tether claims to hold an equivalent amount of reserves denominated in US dollars or dollar-equivalent assets. This 1:1 peg is what gives USDT its stability.
How the Dollar Peg Works
Tether maintains the peg through a reserve-backed model. When an authorized customer deposits US dollars with Tether, the company mints an equal amount of USDT tokens. When tokens are redeemed, they are destroyed (burned) and the corresponding fiat is returned. This issuance-and-redemption cycle, combined with arbitrage activity on secondary markets, keeps the price anchored near $1.00.
In practice, USDT's price occasionally deviates by a fraction of a cent — briefly trading at $0.998 or $1.002 — but arbitrage traders quickly close these gaps by buying cheap USDT when it dips below the peg and selling when it trades above.
What Backs USDT?
Tether publishes quarterly attestation reports prepared by an independent accounting firm. According to these disclosures, the majority of reserves are held in US Treasury bills — short-dated government securities considered among the safest financial instruments. The remaining reserves include cash and cash equivalents, money market funds, secured loans, corporate bonds, and other investments.
As of mid-2025, Tether reports that over 80% of its reserves consist of Treasury bills and overnight reverse repurchase agreements. The company has gradually shifted toward more conservative, liquid assets following years of scrutiny over the composition of its reserves.
Scale and Adoption
USDT is the largest stablecoin by market capitalization — surpassing $140 billion in circulation as of 2025. It consistently ranks among the top three cryptocurrencies by total market cap, behind only Bitcoin and Ethereum. Tether is available on more than ten blockchain networks, including Ethereum (ERC-20), Tron (TRC-20), Solana (SPL), TON, Avalanche, Polkadot, and others.
The primary use cases for USDT include:
- Trading pairs — USDT is the most common quote currency on crypto exchanges, forming the base of spot and derivatives markets worldwide.
- Cross-border remittances — People send USDT internationally as a faster, often cheaper alternative to traditional wire transfers, especially in corridors underserved by banking infrastructure.
- Store of value — In countries with high inflation or limited access to US dollar banking, USDT provides a way to hold dollar-denominated value without a traditional bank account.
- DeFi collateral — USDT is used as collateral in decentralized lending protocols, liquidity pools, and yield farming strategies.
Risks and Considerations
USDT is not a government-backed currency and carries counterparty risk. Users must trust that Tether Operations maintains sufficient reserves to back every token in circulation. While attestation reports provide periodic snapshots, they are not full financial audits — a distinction Tether's critics frequently highlight.
Tether has faced regulatory actions in the past. In 2021, the company settled with the New York Attorney General over allegations of misrepresenting reserve backing, paying an $18.5 million fine. The Commodity Futures Trading Commission (CFTC) also fined Tether $41 million for similar misstatements.
Additionally, USDT can be frozen by Tether at the smart-contract level. The company has frozen addresses associated with sanctioned entities and law enforcement requests, which means tokens held in a wallet are not immune to external intervention.
USDT vs. USDC
The second-largest USD stablecoin is USDC, issued by Circle. While both maintain a dollar peg, they differ in transparency, regulatory posture, and market share. Circle publishes monthly attestation reports and has pursued closer relationships with US regulators. USDC's reserves are held almost entirely in US Treasuries and cash at regulated financial institutions. USDT commands a larger market share and deeper liquidity on most exchanges, while USDC is generally preferred by institutional users and those operating within US regulatory frameworks.