How Do Stablecoins Work? Now Backed by Law

A stablecoin is a crypto token engineered to always trade for $1, and how do stablecoins work comes down to one mechanism: an issuer holds something valuable off-chain or on-chain and lets you redeem your token for that value on demand. The total stablecoin market is worth roughly $300-310 billion as of late August 2026, down from a May peak near $320 billion, and it exists because trading crypto-to-crypto is fast and cheap, while trading crypto-to-bank-dollars is slow and expensive. A stablecoin is the workaround: a dollar that lives on a blockchain.

That sounds simple, but "backed by dollars" hides three genuinely different designs, and the gap between them is the part most readers get wrong.

The dominant model, used by Tether's USDT and Circle's USDC, is fiat-collateralized: the issuer holds roughly $1 in cash and short-term U.S. Treasury bills for every token in circulation, and authorized institutional partners can redeem tokens for real dollars at par. This pair alone is about 82-83% of the entire stablecoin market, with USDT holding roughly 59% share and USDC around 24%.

The second model is crypto-collateralized. Instead of dollars, the reserve is other cryptocurrencies, usually ether or bitcoin, locked in a smart contract. Because crypto is volatile, these systems over-collateralize, often putting up $1.50 or more in crypto for every $1 of stablecoin issued, and the contract automatically liquidates collateral if its value falls too close to the peg. It is more decentralized than a bank-style reserve, but also more fragile in a sharp crypto crash, since a fast-enough price drop can outrun the liquidation mechanism.

The third model is algorithmic: no real collateral at all, just code and incentives. These systems mint or burn tokens to nudge the price back to $1, relying on traders to arbitrage the difference for profit. It is the cheapest design to run, and the one that has failed the most often.

An algorithmic peg only holds if arbitrageurs keep showing up to trade it back to $1, and that assumption breaks precisely when it matters most: during a panic, when everyone wants out at once and no one wants to be the buyer defending the peg. Without a hard, redeemable dollar reserve sitting behind the token, there is nothing to arrest the fall once confidence cracks, and the token can spiral toward zero within hours. This pattern has repeated across multiple algorithmic designs over the past several years, and it remains the standing cautionary case behind every "is this stablecoin safe" question. The practical rule for readers: if a stablecoin's stability depends on a trading incentive rather than a redeemable reserve you can point to, it carries meaningfully more risk than the fiat-backed majority of the market.

Until now, the fiat-backed model has run largely on trust: issuers publish attestations about their reserves, but "we hold $1 for $1" has historically been a claim to verify, not a legal guarantee. That is what's changing. On August 18, 2026, the U.S. Treasury published a formal rulemaking proposal under the GENIUS Act, the federal law governing payment stablecoins, that would codify exactly what "backed 1:1" must mean for issuers operating in the U.S.: specific reserve composition, redemption rights, and disclosure standards, enforceable rather than voluntary. The proposal is open for public comment through October 19, 2026, so nothing is final yet, but it marks the first time the core promise behind fiat-backed stablecoins moves from a market convention to a codified legal obligation.

USDT and USDC use the same fiat-collateralized structure, yet they represent different bets. USDT has by far the largest market cap and the deepest trading liquidity across exchanges worldwide, built over years as the default settlement currency of crypto trading. USDC has leaned harder into regulatory compliance and transparency, and it has been overtaking USDT specifically on adjusted settlement volume, the more institutional, less trading-driven measure of stablecoin use. The GENIUS Act's push toward legally mandated audits and disclosure plays to USDC's existing posture, which is likely why institutional flows have been tilting toward it even as USDT keeps its lead on raw market cap and everyday trading volume.

The most common misunderstanding is treating "stablecoin" as one product with a single risk profile. It isn't. A fiat-backed token redeemable for cash held in short-term Treasuries carries a fundamentally different risk than a crypto-collateralized token that can be forced into liquidation, which is different again from an algorithmic token with no reserve at all. The second misunderstanding is assuming a stable price means a stable legal claim: even among fiat-backed issuers, redemption rights, audit frequency, and reserve quality vary, and that is exactly the gap the GENIUS Act rulemaking is trying to close. Until the comment period ends and a final rule lands, the honest answer to "is my stablecoin safe" depends on which of the three models it uses, and, within the fiat-backed group, on how seriously that specific issuer takes the disclosure standards regulators are now writing into law.