What Happens When Stablecoins Fail

A failure-mode catalog with case studies — algorithmic death spirals (Terra/UST), reserve-bank failure (USDC/SVB), regulatory shutdown (BUSD), issuer fraud (Tether 2021 settlement), and what users actually do when a peg breaks.

29 min · intermediate · part of Stablecoins & Pegged Assets

The Stablecoin Failure Question

A stablecoin that holds its peg is invisible. A stablecoin that breaks its peg is the only thing anyone wants to talk about. The previous lessons in this module covered how stablecoins are supposed to work — fiat-backed, crypto-backed, algorithmic — and why the post-GENIUS market structure looks the way it does. This lesson is the opposite: it walks through every major mode in which stablecoins have failed in the modern era, with named case studies, dollar amounts, dates, and the specific recovery mechanisms (or lack thereof) that played out. The failure catalog matters for two reasons. First, **survivor bias is real**. The stablecoins on your screen today are the survivors. Many predecessors broke their pegs catastrophically and disappeared. Treating today's lineup as "stable" without understanding the failures that produced it is dangerous. Second, **failure modes do not generalize**. A fiat-backed stablecoin can fail through a banking-partner collapse but not through an algorithmic death spiral. An algorithmic stablecoin can fail through an arbitrage-incentive collapse but not through a custodian fraud. Knowing which failure modes apply to which design lets you actually price the risk you are taking when you hold a particular token. We do not re-cover what stablecoins are or the basic types (Lessons 1, 2, 3) or the post-GENIUS regulatory map (Lesson 4). The focus here is failure: what has happened, what has not yet happened, and what to watch for.

Also in this lesson

Failure Mode 1: Algorithmic Death Spiral — Terra/UST
Failure Mode 2: Reserve Bank Failure — USDC and SVB
Failure Mode 3: Regulatory Shutdown — BUSD
Failure Mode 4: Issuer Fraud — Tether 2021 Settlement
Failure Modes 5-7: Smart Contract Bugs, Oracle Failures, and Custodian Compromise
How Recovery Actually Works
Risk-Stratified Portfolio Approach
Watching for the Next Failure
For Deeper Reading

Key terms

Algorithmic death spiral: A failure mode in mint-burn algorithmic stablecoins where the volatile counterpart token (LUNA in Terra) inflates rapidly as the stablecoin (UST) depegs, accelerating the depeg in a self-reinforcing loop. The Terra/UST collapse of May 7-12, 2022 is the canonical case.
Terra/UST collapse (May 7-12, 2022): A roughly $45-60B combined market-cap loss in less than a week. UST fell from $1.00 to approximately $0.10; LUNA expanded from approximately 342M tokens to over 6.5T (a roughly 19,000x dilution) and lost essentially all value. The collapse triggered the broader 2022 crypto credit crisis (3AC, Celsius, Voyager).
USDC/SVB depeg (March 11, 2023): A temporary depeg of USDC after Silicon Valley Bank failed and Circle disclosed approximately $3.3B in trapped reserves. USDC traded as low as $0.87 on Coinbase before recovering to $1.00 within 48 hours after a U.S. Treasury/FDIC/Fed joint guarantee of all SVB deposits.
Systemic risk exception: The legal mechanism under which the U.S. Treasury, FDIC, and Federal Reserve guaranteed all SVB depositors regardless of FDIC insurance limits on March 12, 2023. The mechanism is extraordinary and is not a baseline expectation for future stablecoin depegs.
BUSD shutdown (Feb 13, 2023): The New York Department of Financial Services (NYDFS) order to Paxos to stop issuing new BUSD. Existing BUSD remained redeemable at par through wind-down. Market cap fell from approximately $16B at the order to roughly $1B by year-end 2023; no holder lost principal.
Tether 2021 CFTC settlement (Oct 15, 2021): A $41M settlement in which the CFTC found that Tether held sufficient fiat reserves to back USDT in circulation on only 27.6% of days from June 1, 2016 through February 25, 2019. The NYAG separately settled for $18.5M (Feb 23, 2021), having documented an $850M concealed loss at payment processor Crypto Capital.
BDO Italia attestations: The independent quarterly attestation reports Tether commissions from BDO Italia documenting USDT reserve composition. Replaced earlier, less rigorous reports as part of the post-2021 transparency commitments.
MakerDAO Black Thursday (March 2020): A March 12-13, 2020 oracle-latency event in which a sharp ETH price drop caused under-collateralized vault auctions to settle at zero MKR bids, creating a multimillion-dollar shortfall the DAO socialized through emergency MKR mints. The defining stablecoin oracle-failure case study.
Arbitrage incentive: The structural mechanism by which a fiat-backed stablecoin maintains its peg: any deviation creates a profit opportunity for arbitrageurs to redeem at par (or mint at par) and capture the spread. Breaks down when redemption is suspended, gated, or operationally impaired.
Redemption window: The committed timeframe in which a stablecoin issuer will redeem tokens for fiat. USDC and USDT advertise 24-hour redemption for verified institutional accounts; retail typically uses secondary markets. The credibility of the redemption window is what makes the peg credible.
Custodian compromise risk: The risk that a third-party custodian holding stablecoin reserves (BNY Mellon, State Street, Cantor Fitzgerald, regional banks) suffers a hack, theft, or fraud event. No major regulated stablecoin has yet suffered a custodian-fraud-driven loss; the SVB failure was conventional bank collapse rather than fraud.
Risk-stratified stablecoin portfolio: A treasury practice that splits stablecoin balances across (1) regulated fiat-backed tokens (USDC, USDT) for default working capital, (2) yield-bearing tokens (sUSDS, sUSDe) with explicit risk acceptance, and (3) a small decentralized hedge (USDS, GHO, crvUSD) against centralized-issuer restrictions.

Continue this lesson — 9 more sections in the CryptoBipto app.

Open lesson

Educational only — not financial advice.