A stablecoin is a token designed to hold a steady value — almost always one US dollar. People treat them like cash: a place to park money between trades, move value across exchanges, or earn yield. The catch is that “$1” is a promise, and a promise is only as good as whatever stands behind it. Stablecoins don’t all break in the same way because they aren’t all backed the same way.

If you hold any meaningful amount, it’s worth understanding what’s actually under the hood — because the difference between “boringly safe” and “one bad week from zero” comes down to the backing model.

The three backing models

Fiat-backed (reserve-backed)

The issuer claims to hold one real dollar (or near-cash equivalent like short-term Treasuries) for every token. This is the most common and, done honestly, the most robust. The risks here aren’t exotic — they’re old-fashioned:

  • Reserve quality: are the reserves actually cash and short-dated Treasuries, or riskier paper that can wobble in a crisis?
  • Reserve proof: is there a real, regular audit (not just an “attestation”), and by whom?
  • Custody and counterparty: where are the reserves held, and what happens if that bank or custodian fails? (A major stablecoin briefly depegged in 2023 purely because some reserves sat in a bank that collapsed — the token was “fine,” its bank wasn’t.)

Crypto-collateralized

Backed by other crypto, locked up as collateral and usually over-collateralized (e.g. $150 of crypto backing $100 of stablecoin) to absorb price swings. More decentralized, but the backing is volatile by nature. The risk is reflexive: in a sharp crash, the collateral falls, positions get liquidated, and the mechanism is stressed exactly when markets are already chaotic.

Algorithmic

Backed by little or no real collateral — stability is supposed to come from code, incentives, and a partner token that absorbs volatility. This is the model that has failed most catastrophically. When confidence breaks, the “stabilizing” mechanism can spiral instead, and the coin can go to near-zero in days. Treat pure algorithmic stablecoins as a high-risk experiment, not a cash substitute.

Why stablecoins depeg

A depeg is when the token trades meaningfully away from $1. It usually traces to one of a few things:

  • Reserve doubt — the market stops believing the backing is real or accessible, and everyone tries to redeem at once.
  • A broken redemption path — if you can’t reliably swap the token for $1, arbitrage can’t hold the peg.
  • Collateral collapse (crypto-backed) or confidence collapse (algorithmic).
  • Liquidity crunch — thin order books let a few large sellers push the price down fast.

The pattern is almost always a confidence problem becoming a liquidity problem. The peg holds because people believe it will; when belief cracks, the exits get crowded.

What to actually check

Before you trust a stablecoin with real money, run a short checklist:

  • What backs it? Fiat reserves > crypto collateral > algorithmic, in rough order of safety.
  • Can you verify the reserves? Real audits beat vague “attestations.” No transparency is a red flag.
  • What’s the redemption path? Can large holders actually redeem for $1, and how fast?
  • Where does the risk concentrate? One bank, one custodian, one collateral asset, one jurisdiction?
  • How deep is liquidity on the venues you’d actually exit through?
  • Regulatory standing in your jurisdiction — stablecoin rules have tightened, and that cuts both ways (more oversight, but also possible access changes).

The mental model

Hold a stablecoin and you are an unsecured creditor of the issuer, betting their backing is real and redeemable. That’s a very different thing from holding actual dollars in an insured bank account, even though the balance reads the same. It can be a perfectly reasonable bet with a transparent, well-reserved, audited issuer — and a terrible one with an opaque or algorithmic project promising yield that has to come from somewhere.

This is the same custody-risk lens that applies across crypto: the balance on a screen is a claim, not a guarantee. We use it on exchanges and platforms too — see the crypto betting platforms risk guide for the same logic applied to operators holding your funds.

FAQ

Are stablecoins safe?

The best fiat-backed ones, with transparent audited reserves, are reasonably safe for short-term use — but never as safe as insured bank dollars. Crypto-collateralized ones carry volatility risk, and algorithmic ones have repeatedly failed. “Stable” describes the goal, not a guarantee.

Why did a stablecoin lose its peg if it was “fully backed”?

Backing can be real but temporarily inaccessible — for example, if reserves sit in a bank that fails. The token’s value depends on reserves being both sufficient and reachable, plus a working redemption path and enough liquidity.

Is yield on a stablecoin free money?

No. Yield has to be generated by lending, trading, or risk-taking somewhere. Higher advertised yield generally means more hidden risk in how it’s produced. Always ask where the yield actually comes from.

Bottom line

A stablecoin is only as stable as what backs it and whether you can redeem it. Favor transparent, audited, fiat-reserved issuers; treat algorithmic models as speculation; and remember that holding one makes you a creditor, not a cash holder. The dollar sign on the balance is a promise — check who’s making it before you trust it.