What Are Stablecoins and How Do They Stay Stable?

A stablecoin is a cryptocurrency designed to keep a stable value by tracking the price of a reference asset, most commonly the US dollar. The idea is to combine the fast, borderless transferability of blockchain transactions with the predictable purchasing power of traditional money. In practice, stablecoins are the plumbing of much of the crypto economy: traders move between volatile assets and stable ones, and people in countries with unstable local currencies use dollar-pegged tokens for savings and payments.

Fiat-backed stablecoins

The most common design is the simplest to describe: a company issues tokens and holds equivalent reserves — cash and short-term government securities — in traditional accounts. One token is supposed to represent one dollar sitting in a reserve. Users can typically redeem tokens for the underlying currency, and that redemption promise is what anchors the market price. The critical questions with this model are transparency and trust: how good are the reserves, who audits them, and how quickly can redemptions be honored under stress? Large issuers publish regular attestations, but an attestation is a snapshot review, not a full audit, so understanding the difference matters.

Crypto-collateralized stablecoins

A second design backs stablecoins with other cryptocurrencies rather than with bank money. Because crypto assets are volatile, these systems require overcollateralization: to mint 100 dollars' worth of stablecoin, users may need to lock up 150 or 200 dollars' worth of collateral in smart contracts. If the collateral's price falls too far, the system automatically sells part of it to maintain the peg. This model removes reliance on traditional banks and makes reserves visible on-chain, but it introduces its own complexity: rapid market crashes can stress liquidation mechanisms, and the code itself becomes a point of failure.

Algorithmic stablecoins

The third family tried to maintain the peg through incentives and market arbitrage alone, expanding or contracting token supply without full reserve backing. History has been unkind to this approach. The collapse of TerraUSD (UST) in May 2022 is the canonical example: within days, a design that had grown to tens of billions of dollars in circulation lost its peg entirely and entered a death spiral, wiping out enormous value and triggering a broader market downturn. The lesson is not that every algorithmic design will fail, but that a peg without credible, verifiable backing depends entirely on confidence — and confidence can evaporate faster than any mechanism can react.

What people actually use them for

• Moving value across borders in minutes instead of days, often at lower cost than legacy remittance rails.
• Holding dollar-equivalent balances where access to USD bank accounts is difficult or expensive.
• Bridging between volatile crypto assets without leaving the blockchain ecosystem.
• Settling transactions in on-chain applications where a predictable unit of account is needed.

Risks to understand before relying on any of them

Stablecoins reduce exposure to crypto price swings, but they are not risk-free. Counterparty risk means the issuer or the custodian of reserves could fail or mismanage assets. Regulatory risk is significant: stablecoins sit at the intersection of banking and crypto, and rules differ by jurisdiction and are still evolving. Technical risk applies to the smart contracts that manage collateral. And transparency risk — not knowing exactly what backs a token — has historically been where the worst outcomes originate. Reading an issuer's reserve reports and redemption policies is part of basic due diligence.

Key takeaways

Stablecoins are tools, not magic. Their stability comes from a mechanism — reserves, collateral or incentives — and every mechanism has failure modes. Fiat-backed designs dominate because their promise is easiest to verify; crypto-collateralized designs trade bank reliance for code reliance; and history shows what happens when a peg leans mostly on confidence. Treat any stablecoin as a claim on someone else's arrangements, and evaluate the arrangements before trusting the claim.