Stablecoin Depegs Explained: What Happens When a Digital Dollar Breaks the Buck

Stablecoins are marketed as digital dollars that always trade at $1, but market data shows repeated depegs that can erode billions of dollars in value. Recent price drops for USDC, USDT, and the collapse of TerraUSD (UST) illustrate how confidence, banking issues, counter‑party risk, and design flaws can break the peg.

Why the Peg Is Not a Legal Guarantee

The $1 price is an economic promise, not a code‑enforced rule. Issuers claim each token can be redeemed for one US dollar, and arbitrage traders keep the market price near $1 by buying discounted tokens and redeeming them, or by minting new tokens when the price is above $1. The effectiveness of this mechanism depends on the ability of traders to access redemption channels, which often have high minimums or verification requirements.

Four Recent Depegs and Their Causes

• October 2018 – USDT: Rumors about Tether’s solvency caused the token to dip to about $0.88 on some venues. Reserves later covered redemptions and the peg recovered within days.
• March 2023 – USDC: Circle disclosed that $3.3 billion of its reserves were frozen at the failed Silicon Valley Bank, pushing USDC to $0.87. The price rebounded after U.S. regulators guaranteed the bank’s deposits.
• November 2025 – xUSD (Stream Finance): The yield‑bearing stablecoin relied on leveraged strategies with external fund managers. A disclosed $93 million loss led to a freeze of withdrawals and a price collapse to as low as $0.24.
• May 2022 – TerraUSD (UST): An algorithmic design linked UST to LUNA. Large withdrawals broke the peg, triggering a sell‑off of LUNA that hyper‑inflated its supply and caused UST to fall below $0.10, erasing roughly $40 billion across UST and LUNA.

2026 Market Contraction

New U.S. federal stablecoin regulations eliminated interest payments on digital dollars, prompting capital outflows. The total stablecoin supply peaked near $322 billion in mid‑May 2026 and then fell by $14.56 billion by early August, the sharpest decline since the Terra collapse. USDT fell from about $189 billion to $183.2 billion, while USDC dropped from $80 billion to $72.1 billion. Smaller tokens also saw volume losses, with Sky Dollar’s USDS posting the steepest weekly decline.

Concentration Risks

USDT and USDC together represent roughly 83 % of the $307.6 billion stablecoin market, meaning the redemption infrastructure relies heavily on two issuers’ banking relationships. Shocks to either issuer—such as a banking failure, regulatory action, or reserve dispute—can have outsized effects on the broader market.

Reading Future Depegs

1. Identify the root cause: reserve‑backed tokens often recover once redemption is proven, whereas algorithmic or opaque yield‑linked designs may not.
2. Monitor redemption activity, not just price, to gauge whether a discount reflects temporary market sentiment or a deeper liquidity issue.
3. Watch contagion pathways: past depegs have affected collateralized assets like DAI and broader DeFi lenders.