Stablecoins Explained

05 September 2026

A stablecoin is a cryptocurrency designed to maintain a fixed value - most commonly one US dollar. The word "designed" is doing heavy work there. Keeping a digital token worth exactly one dollar in a market that trades 24/7, across dozens of blockchains, requires mechanisms that vary dramatically in how they work and how reliably they hold. Some stablecoins have held their peg for years through bank runs, market crashes, and regulatory pressure. Others have collapsed to zero in hours.

This page maps the entire territory: how different stablecoin types hold their peg, what happens when they fail to, and where you should go for a deep understanding of each mechanism, risk, and decision.

How stablecoins maintain their peg: the core mechanisms

Every stablecoin solves the same problem: a token that trades freely on exchanges will drift away from its target price unless something pulls it back. The something varies. Four fundamentally different approaches exist, and each has its own failure modes.

Fiat-Backed and reserve models

The simplest explanation a newcomer hears is that stablecoins are backed 1:1 by cash in a bank account. That is the first misconception this subject sheds. How Fiat Backed Stablecoins Keep Their 1 to 1 Peg answers the real question: how do issuers like Circle and Tether actually maintain parity through a combination of reserve assets and a mint-and-redeem mechanism? When USDC trades at $0.99 on an exchange, a trader can buy it, redeem it through Circle's API for $1 worth of assets, and pocket the difference. That arbitrage loop is the engine. But the reserve is never 100% cash. Commercial paper, Treasuries, and overnight repos all carry their own risks.

The Mint and Redeem Arbitrage Loop That Restores Stablecoin Pegs drills into how that loop works in practice - and what happens when it breaks. The mechanism is elegant: if the token trades above $1, minters create new tokens by depositing dollars and sell them into the market for profit. If it trades below $1, redeemers buy cheap tokens and cash them in at par. The loop self-corrects as long as arbitrageurs have a clear path to mint or redeem. When redemptions pause or the issuer freezes withdrawals, you get the second-order effects covered later.

Crypto-Overcollateralized Vaults

Some stablecoins escape reliance on bank accounts entirely by using cryptocurrency as backing. How Crypto Overcollateralized Stablecoins Work and Stay Pegged explains the DAI model: users deposit Ethereum or other collateral into a Maker vault, then mint DAI against it. They must overcollateralize - typically 150% or more - so that even if the collateral drops in value, the system remains solvent. If the collateral ratio falls below a liquidation threshold, the vault is auctioned off. The stability fee (a variable annual rate paid on outstanding DAI) acts as a demand lever: raise it to reduce supply when DAI trades below peg, lower it to encourage borrowing when DAI trades above.

How Stability Fees and Interest Rates Control Stablecoin Pegs takes this further. The fee is not static. MakerDAO governance votes on rates per collateral type. When DAI traded at $1.05 in 2020, the protocol raised stability fees from 0.5% to 8.5% over several months. It worked. The mechanism is blunt but effective - until it hits the limits covered in collapse scenarios.

Algorithmic seigniorage and supply control

A third family attempts to hold a peg without collateral at all, by algorithmically expanding and contracting token supply. Algorithmic Seigniorage Stablecoins and Expansion Contraction Cycles explains the model made famous by TerraUSD (UST) and its failure. The idea: when the token trades above peg, mint new tokens and distribute them to holders, diluting the price down. When it trades below, shrink supply by burning tokens or issuing a volatile "share" token that absorbs the loss. In theory, the system rebases supply across all wallets. In practice, the death spiral - where a falling peg triggers supply expansion that makes holders sell faster, which drops the peg further - has killed every algorithmic stablecoin that tried pure seigniorage. The Terra collapse in May 2022 erased $40 billion and proved the model cannot survive a sustained confidence crisis.

Delta-Neutral Hedging

The newest approach uses derivatives markets. Delta Neutral Hedging Stablecoins Using Perpetual Futures Funding Rates examines Ethena's USDe model: take deposited ETH, short an equivalent amount of ETH perpetual futures, and earn funding rate payments from the longs. The delta is neutral - ETH can move up or down without affecting the stablecoin's backing - because every spot position is offset by a short perpetual. The yield comes from funding rates, which historically pay longs in bull markets and shorts in bear markets. The risk: negative funding periods can bleed the reserve, the custodian holding the short position can go insolvent, and the futures exchange can halt trading during extreme volatility.

Collapse mechanisms: what happens when pegs break

No stablecoin is immune to depegging. The difference between a survivable wobble and a fatal collapse comes down to the specific mechanism and the size of the run.

Depeg cascades and liquidation spirals

What Happens When Stablecoins Depeg and Trigger Liquidation Cascades walks through the mechanics of a collapse in detail. A small depeg - say DAI slipping to $0.98 - can trigger a cascade if the market holds significant leveraged positions using that stablecoin as collateral. On Compound or Aave, a user who borrowed DAI against ETH sees their health factor drop as DAI loses value. They must repay or get liquidated. Liquidations sell the ETH collateral into the market, pushing ETH down, which triggers more liquidations in Maker vaults, which forces more DAI minting to repay debt, which pushes DAI further below peg. The loop accelerates.

The user will see errors like "Liquidation penalty applied" after a vault is auctioned, or "Bad debt accrued" if the liquidation does not cover the debt. Protocols like Maker and Liquity have survival mechanisms - delayed liquidations, re-pricing, debt auctions - but none guarantees a stop.

Oracle manipulation and governance attacks

Stablecoins that rely on external price feeds are vulnerable to oracles reporting false prices. Oracle Manipulation Attacks Triggering False Stablecoin Vault Liquidations covers the scenario where a manipulated Chainlink or custom oracle reports ETH at $1500 when the real price is $1800, triggering liquidations on perfectly healthy vaults. The attacker buys the auctioned collateral at a discount. Some protocols mitigate with TWAP oracles or redundant feeds; others have been exploited.

Smart Contract Exploits That Drain Stablecoin Minting Contracts and Reserves explains exploits that drain the minting contract itself. In the Cream Finance exploit, attacker borrowed liquidity and manipulated price oracles to drain $130 million from the Iron Bank. The stablecoin's peg evaporated because the reserve backing it was gone.

Regulatory freeze and custodian insolvency

Centralized stablecoins face a different failure mode: the issuer freezes addresses or the custodian goes bankrupt. Regulatory Freeze of Stablecoin On Chain Contracts by Compliance Modules examines how Circle and Tether can and do freeze addresses on-chain through their smart contract upgrade keys. In 2022, Circle froze over 75,000 USDC addresses tied to the Tornado Cash sanctions. The frozen tokens are unusable in DeFi but remain redeemable through Circle if the owner is not sanctioned. If the issuer's bank collapses (as with Silvergate and Signature in 2023), redemptions stop entirely.

Fractional Reserve Stablecoins and the Risks of Partial Backing addresses the scenario where a stablecoin is only partially backed - holding only a fraction of the dollars it claims. If every holder tries to redeem simultaneously, only the first to arrive get their money. The error message "Redemption paused" during high volatility is the canary. How Real Time On Chain Proof of Reserves Verification for Stablecoins Works explains what an attestation actually proves - that a snapshot existed at a moment in time, not that the reserves are still there.

Tools for Monitoring and Interacting with Stablecoins

Participants in the stablecoin ecosystem use specialized tools to mint, redeem, monitor, and exit. Each tool carries its own risks and costs.

The primary mint-and-redeem portals for the largest stablecoins are the Circle Mint and Redeem API for USDC and the Tether.to account portal for USDT fiat redemptions. Both require institutional verification. Retail users interact through exchanges like Coinbase or Binance, where redemption is indirect and fees apply. MakerDAO Oasis.app for DAI vault management lets users mint DAI against collateral, with the error "Insufficient collateral to mint" appearing when the ratio falls below minimum.

For monitoring, DefiLlama stablecoin dashboard and transparency pages track supply, reserves, and peg deviation across all major stablecoins. Dune Analytics peg-deviation dashboards are built by the community and show real-time deviation in basis points. Arkham Intelligence entity-tagged reserve wallets tracks large holder movements and issuer wallet balances.

For traders during a depeg, Curve 3pool and stableswap invariant pools remain the primary exit route. The error "Slippage exceeded" on a stableswap pool during depeg signals liquidity drying up. Peg Stability Module (PSM) for fixed-rate swaps exists on Maker (for DAI-USDC) and Frax (for FRAX-USDC), allowing users to swap at exactly $1 regardless of market price - until the module is drained.

Key decisions users face

Participants make real decisions about which stablecoin to hold, where to deploy it, and what to do during stress.

USDC vs USDT for Exchange Settlement and Withdrawal Routes Compared breaks down the tradeoff: USDT has deeper liquidity on most centralized exchanges and wider global redemption routes, but USDC has stronger regulatory compliance, more transparent attestations, and direct redemption through Circle. The cost difference in fiat redemption fees and minimum thresholds is material for high-volume traders.

DAI vs USDC for DeFi Lending Collateral Yield Compared examines the centralization vector. USDC is solvent and liquid but censorable - Circle can freeze it. DAI is governed by MakerDAO but holds USDC and other centralized assets as collateral, so it is not fully decentralized. The yield differential between lending DAI and USDC on Aave or Compound reflects this risk asymmetry.

Centralized Fiat Backed vs Decentralized Crypto Backed Stablecoins Compared provides the full tradeoff analysis. Capital efficiency favors fiat-backed (100% reserve vs 150%+ overcollateralization). Censorship resistance favors crypto-backed. The real risk is not which model is better, but whether you need to worry about either side's failure mode.

Native USDC vs Bridged USDC.e Risk Profile on Arbitrum and Optimism clarifies which version of USDC on L2s carries bridge risk. Bridged USDC.e, issued by the canonical bridge, can become insolvent if the bridge is exploited. Native USDC, issued directly by Circle on each chain, cannot. The error "Withdrawal queue depth exceeded" on LSD-backed stablecoins is specific to liquid staking derivatives that back stablecoins like sUSDe.

Curve 3pool LP vs Single Sided Staking for Stablecoin Yield Compared helps yield seekers understand the depeg risk. LPing in the 3pool exposes you to impermanent loss during a depeg - if USDC drops to $0.90, your LP share rebalances into more USDC. Single-sided staking on platforms like Morpho or Gearbox avoids that concentration risk but carries its own lending protocols risks.

How to Redeem During a Mild Depeg or Wait for Arbitrageurs is the practical question every holder faces. The answer depends on the stablecoin's mechanism. For USDC and USDT, waiting usually works - the arbitrage loop is reliable. For algorithmic stablecoins, selling early is often the correct move, because the death spiral accelerates. The error "Depeg threshold breached" on a risk monitoring dashboard is the signal to decide.

The broader landscape: comparisons and misconceptions

The stablecoin space is full of claims that do not survive scrutiny. "All stablecoins are backed 1:1 by cash in a bank account" is false for DAI, Frax, LUSD, and every algorithmic variant. "USDT and USDC are audited the same way" ignores that USDC publishes monthly attestations from a Big Four firm, while USDT has historically released quarterly breakdowns with narrower scope. "DAI is fully decentralized" ignores that nearly half its collateral was USDC at points in 2023, meaning a Circle freeze could take down DAI.

"A stablecoin that has never depegged is safe" is the most dangerous belief. USDC depegged to $0.87 on March 11, 2023, when Silicon Valley Bank collapsed holding some of its reserves. It had never depegged before. The mechanism was broken not by market speculation but by a bank run on a single depository institution.

The comparisons in depth - Ethena USDe vs DAI Yield Source and Sustainability, crvUSD vs Frax Liquidation Mechanism, GHO vs crvUSD Borrow Model, LUSD vs RAI Floating Redemption Price Models, PayPal PYUSD vs Circle USDC Issuer Trust - are the subject of individual spoke pages linked below.

This page has mapped the terrain. Each spoke below answers one question completely, with the tools, errors, costs, and specific mechanisms that matter for that piece of the stablecoin world.

Read the spoke that matches your question:

• How Fiat Backed Stablecoins Keep Their 1 to 1 Peg - the reserve and redemption mechanism for USDC, USDT, and similar models
• How Crypto Overcollateralized Stablecoins Work and Stay Pegged - DAI's vault, liquidation, and stability fee system
• **Algorithmic Seigniorage Stablecoins and Expansion Contraction Cycles

Back to stablecoins