Peg/De-Pegging
Lexicon Core Definition
A peg is a mechanism that maintains a cryptocurrency's price at a fixed target value, typically one US dollar. De-pegging occurs when market forces or design failures cause the price to deviate significantly from that target.
Analysis Breakdown
Frequent Queries
What does it mean for a stablecoin to de-peg?
De-pegging occurs when a stablecoin's price moves significantly away from its intended fixed value — typically one US dollar. Minor de-pegs are temporary deviations of a few cents during periods of market stress, usually corrected quickly by arbitrageurs. Severe de-pegs indicate that the mechanism maintaining the peg has failed or been overwhelmed by selling pressure. TerraUSD's 2022 collapse is the most extreme example — an algorithmic stablecoin that fell from $1.00 to near zero within days, wiping out billions in value. The severity and permanence of a de-peg depends entirely on the underlying peg design and its resilience to adversarial conditions.
Are all stablecoins equally safe from de-pegging?
No. Stablecoin safety differs significantly based on the mechanism maintaining the peg. Fiat-backed stablecoins with fully audited reserves and direct redemption rights offer the strongest peg stability — they can always redeem tokens at face value as long as reserves are intact. Crypto-collateralised stablecoins carry smart contract and collateral liquidation risks. Algorithmic stablecoins rely entirely on market incentive mechanisms and have the weakest track record — multiple algorithmic designs have collapsed to near zero under stress. Before holding any stablecoin beyond short periods, understanding which category it belongs to and verifying its reserve backing is essential due diligence.
What caused TerraUSD to de-peg and collapse?
TerraUSD was an algorithmic stablecoin that maintained its dollar peg through a reflexive relationship with its sister token LUNA. When UST traded above $1, the protocol incentivised burning LUNA to mint more UST. When UST traded below $1, it incentivised burning UST to mint LUNA. This created a death spiral vulnerability — large UST sell pressure caused the peg to break, which triggered massive LUNA minting to absorb the imbalance, hyperinflating LUNA's supply, collapsing LUNA's price, destroying confidence in the backing mechanism, accelerating further UST selling. The feedback loop wiped out approximately $40 billion in combined value within days in May 2022.
Calibration Check
Stablecoins are completely safe to hold because they are designed to always be worth one dollar.
Stablecoins are designed to maintain a one-dollar peg, but design intent and guaranteed outcome are different things. Every stablecoin carries risk proportional to its peg mechanism. Fiat-backed stablecoins depend on reserve integrity and issuer solvency — USDC temporarily de-pegged when its issuer's bank exposure became public. Crypto-collateralised stablecoins face liquidation cascade risks under severe market downturns. Algorithmic stablecoins have repeatedly collapsed entirely. Treating any stablecoin as equivalent to actual held cash is an error — they carry counterparty, smart contract, or design risks that cash does not.
A stablecoin that has never de-pegged before is safe from de-pegging in the future.
Historical peg stability is informative but not predictive of future behaviour under conditions the stablecoin has not yet faced. Many stablecoin failures occurred to protocols with previously clean records. TerraUSD maintained its peg successfully for years before the conditions triggering its death spiral emerged. Peg resilience is tested most severely during extreme market stress events — precisely the conditions that occur infrequently. Evaluating the structural design of the peg mechanism and stress-testing it against adverse scenarios is more reliable than assuming stability will persist because it has been observed historically.
All pegs target one US dollar and stablecoins are the only pegged crypto assets.
While the most common peg target is the US dollar, pegs exist against other currencies, commodities, and even other cryptocurrencies. Euro-pegged stablecoins, gold-backed tokens, and synthetic assets pegged to equity indices all use similar price stability mechanisms targeting different reference values. Additionally, wrapped tokens maintain a one-to-one peg to their underlying originals through bridge custody — wBTC is pegged to Bitcoin, for example. Understanding the specific peg target and mechanism of any asset claiming price stability is more important than assuming all pegged assets behave identically or share equivalent risk profiles.