How Fiat Backed Stablecoins Keep Their 1 to 1 Peg

05 September 2026

A fiat-backed stablecoin is a token that claims to be worth exactly one dollar. The claim rests on a simple promise: for every token in circulation, the issuer holds one dollar's worth of traditional currency or cash-equivalent assets in a reserve. The peg is not enforced by code. It is enforced by arbitrage.

The Mint-and-Redeem Loop

The mechanism is straightforward. You send one dollar to the issuer. The issuer sends you one token. You now have a digital dollar. When you want your actual dollar back, you send the token to the issuer and they send you one dollar from the reserve.

This creates a natural price anchor. If the token trades above $1 on an exchange, you can mint new tokens at $1 from the issuer and sell them for a profit. That selling pressure pushes the price back down. If the token trades below $1, you can buy it cheap on the exchange and redeem it with the issuer for a full dollar. That buying pressure pushes the price back up.

The loop works as long as two things are true: the issuer honours redemptions at $1, and the reserve actually contains enough money to cover every token.

What the reserves actually are

USDC and USDT are the two largest fiat-backed stablecoins. Both publish monthly attestations from accounting firms. The attestations confirm that the total reserve value equals or exceeds the number of tokens in circulation.

But "cash equivalents" covers a range of assets. For USDC, the reserve includes actual cash in bank accounts, US Treasury bills, and repurchase agreements backed by US government debt. For USDT, the reserve has historically included commercial paper, corporate bonds, secured loans, and other instruments that are less liquid than Treasuries. The difference matters. Cash in a bank account can be returned to a redeemer in hours. A commercial paper position may take days to sell, and may sell for less than its face value in a stressed market.

Attestations are snapshots. They confirm the reserve composition at a single point in time. They do not guarantee that the composition stays the same the next day, or that the assets can be liquidated at the stated value.

The redemption process step by step

A retail user does not usually redeem directly with the issuer. Most users hold stablecoins on exchanges or in wallets that do not offer direct redemption. They sell the token on the open market. The arbitrage is performed by professional traders and market makers who have the accounts and the volume to redeem efficiently.

The process for those who can redeem directly looks like this:

1. Submit a redemption request through the issuer's platform.
2. The issuer verifies the request and checks the user's identity.
3. The issuer burns the tokens on-chain.
4. The issuer initiates a bank transfer for the equivalent amount in US dollars.

Step four is where delays happen. Bank transfers take time. Some issuers process redemptions within one business day. Others take longer. During periods of high demand, the queue can stretch to weeks.

When the process breaks

The peg breaks when the arbitrage loop cannot complete. That happens in three common ways.

Reserve freezes. A bank holding the stablecoin issuer's cash goes into receivership. The funds become inaccessible. The issuer cannot honour redemptions. The token trades below $1 until the funds are released or the issuer finds a way to restore confidence.

Bank runs. If enough token holders try to redeem at once, the issuer may not have enough liquid cash to process all requests. Treasuries and commercial paper must be sold, possibly at a loss. If the losses are large enough, the reserve falls below 1:1. The peg breaks and may not recover.

Attestation delays. The issuer stops publishing attestations. No one outside the company knows whether the reserves still cover the supply. Trust erodes. The token trades at a discount until the issuer provides proof, if they can.

USDC broke its peg in March 2023 when Silicon Valley Bank failed. USDC's issuer held $3.3 billion of the reserve at SVB. The token traded as low as $0.87 on some exchanges. The peg was restored not by the stablecoin's design, but by a government backstop.

USDT has faced similar stress during market crashes. In May 2022, after the collapse of Terra's UST, USDT traded at $0.95 for several days. The issuer continued processing redemptions and the peg eventually returned. The episode demonstrated that a fiat-backed stablecoin can survive a run if the reserves are real and the issuer keeps the redemption window open.

The Core Weakness

A fiat-backed stablecoin is only as trustworthy as its issuer and its auditors. The peg depends on a promise, a bank account, and a quarterly accounting report. Those are not smart contracts. They are institutions. Institutions can fail.

The arbitrage loop is elegant. But it runs on rails that are outside the blockchain entirely. When those rails break, the stablecoin becomes a token with no guarantee of value, trading at whatever the market believes the issuer can actually return.

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