What Is a Stablecoin? How USDT, USDC and Regulated Digital Dollars Work

Stablecoins explained: how they hold a $1 peg, the four main types, the ~$300 billion market, the GENIUS Act and MiCA, and the risks investors should know.

Oct 08, 2026 - 14:14

Updated: 13 hours ago

What Is a Stablecoin? How USDT, USDC and Regulated Digital Dollars Work

Digital dollar coins balanced against banknotes and treasury bonds on a golden scale

Key takeaways: A stablecoin is a crypto token designed to keep a stable value, usually $1, by holding reserves such as cash and short-term US Treasuries. Stablecoins are the main settlement currency of crypto markets and a growing payment rail. The market is worth roughly $300 billion and is dominated by two issuers, Tether (USDT) and Circle (USDC).

Last updated: October 8, 2026

What is a stablecoin, in one sentence?

A stablecoin is a token on a blockchain that tracks the value of a reference asset, most often the US dollar, so that it can be sent like crypto but priced like cash.

How does a stablecoin keep its peg?

For the dominant, fiat-backed model, the mechanism is simple:

Minting: a customer sends $1 million to the issuer, which creates 1 million tokens.
Reserves: the issuer holds an equal amount in cash, bank deposits or short-term Treasury bills.
Redemption: a customer returns tokens, which are destroyed, and receives dollars back.

This mint-and-redeem loop creates arbitrage. If the token trades at $0.99, traders buy it and redeem it for $1; if it trades at $1.01, they mint new tokens and sell them. As long as reserves are real and redemptions work, the price stays close to $1.

The four types of stablecoins

Type	How the peg is held	Examples	Main risk
Fiat-backed	Cash and T-bill reserves held by an issuer	USDT, USDC	Issuer, custody and banking risk
Crypto-collateralized	Over-collateralized crypto locked in smart contracts	DAI / USDS	Collateral crash, smart-contract bugs
Commodity-backed	Physical gold or other commodities	PAXG, XAUT	Custody and audit quality
Algorithmic	Supply rules and a sister token, little or no collateral	TerraUSD (failed 2022)	Death-spiral collapse

How big is the stablecoin market?

Total stablecoin supply stood at about $303.8 billion on September 2, 2026, according to DefiLlama data. It peaked near $322 billion in May 2026. USDT and USDC together hold roughly 82% of supply, which makes the market highly concentrated.

Market cap measures how many digital dollars exist. Transfer volume measures how much they are used. Adjusted stablecoin settlement volume reached a record of about $1.79 trillion in June 2026.

Why stablecoins matter for crypto markets

Trading collateral: most crypto pairs on exchanges are quoted against USDT or USDC.
Dry powder: stablecoins waiting on exchanges are capital that can buy Bitcoin quickly. The Stablecoin Supply Ratio (Bitcoin market cap divided by stablecoin supply) tracks this; it stood near 4.2 in August 2026. More on how liquidity and institutional flows move prices.
DeFi: lending, borrowing and liquidity pools are largely denominated in stablecoins. See our guide to Web3, DeFi and tokenization.
Payments: cross-border transfers and remittances settle in minutes, at any hour.

How are stablecoins regulated?

United States. The GENIUS Act, signed into law in July 2025, created the first federal framework for payment stablecoins. Issuers must back tokens one-to-one with high-quality liquid reserves such as cash and short-term Treasuries, publish reserve disclosures and operate under federal or state supervision. In July 2026, Circle received final approval from the Office of the Comptroller of the Currency (OCC) for a national trust bank, as we reported here.

European Union. The Markets in Crypto-Assets regulation (MiCA) sets reserve, licensing and disclosure rules for e-money tokens and asset-referenced tokens. Circle's USDC and EURC were among the first major stablecoins to comply.

The broader US market-structure bill, the CLARITY Act, is still stalled in the Senate. See what happens next for the CLARITY Act.

What are the risks?

Depegging: in March 2023, USDC briefly fell to around $0.87 after Silicon Valley Bank, which held part of its reserves, collapsed. It recovered once the deposits were guaranteed.
Issuer risk: holders rely on the issuer's reserves, audits and ability to process redemptions.
Algorithmic failure: TerraUSD lost its peg in May 2022 and wiped out tens of billions of dollars of value.
Freezing: centralized issuers can freeze tokens at specific addresses, often at the request of law enforcement.
Regulatory change: rules differ by country and continue to evolve.

Stablecoins vs CBDCs

A stablecoin is issued by a private company; a central bank digital currency (CBDC) is issued by a central bank. The two paths are diverging: Europe is advancing a digital euro while the US has moved to block a retail CBDC. Read our analysis: Digital Euro vs US CBDC Ban.

FAQ

Are stablecoins safe?

Fully reserved, regulated stablecoins are far safer than algorithmic ones, but none is risk-free. Check the issuer's reserve reports and regulatory status.

Do stablecoins pay interest?

The GENIUS Act prohibits issuers from paying interest directly to holders. Yield offered by third-party platforms carries that platform's risk.

What is the difference between USDT and USDC?

Both are dollar-backed. USDT (Tether) is the largest by supply and most used on offshore exchanges; USDC (Circle) is US-based, publishes monthly attestations and is MiCA-compliant.