Stablecoin yields of eight, twelve, or even twenty percent attract savers who compare them against bank interest rates and wonder why everyone is not doing this. The honest answer is that high yields are not free money; they are payments for risks that are often invisible until they crystallise. A yield is sustainable only if someone is paying for the use of your capital at a rate the underlying activity can support, and when yields far exceed the borrowing demand of real economic activity, the gap is usually filled by leverage, token incentives, or risk that has not yet been priced. Understanding where yield comes from is the first step to judging it.

Legitimate stablecoin yield has three main sources. First, lending: borrowers pay interest to use your stablecoins, often to trade with leverage, and platforms pass most of that interest to lenders. Second, liquidity provision: you earn trading fees for supplying stablecoins to decentralised exchange pools, plus sometimes token rewards. Third, staking-like or real-world-asset strategies: the platform invests in Treasury bills or other assets and shares the return. Sustainable yields from these sources generally track short-term interest rates plus a risk premium, so yields far above that range deserve scepticism rather than excitement.

Unsustainable yields usually come from token emissions, where a protocol pays lenders in its own newly minted token, or from circular leverage, where borrowed funds are redeposited to farm more rewards. Both can produce spectacular headline rates while the underlying economics lose money, and both collapse when token prices fall or when new deposits slow. If a platform cannot explain its yield source in one clear paragraph, or if its yield depends on its own token holding its price, treat the headline rate as marketing rather than income.

Depeg risk is the most direct: a stablecoin can lose its dollar peg, as several have, turning a supposedly stable holding into a double-digit loss overnight. Algorithmic stablecoins carry the highest depeg risk, while fiat-backed stablecoins depend on the quality and transparency of their reserves, which is why proof-of-reserves reporting and reputable audits matter. Smart-contract risk is next: lending protocols and vaults are code, and code has bugs, as years of exploits have demonstrated. A platform audited once two years ago is not the same as one audited recently by a reputable firm with a bug-bounty programme.

Counterparty and platform risk complete the picture. Centralised platforms that offer high yields may lend your funds to hedge funds or trading firms whose positions you cannot see, and if those borrowers default, your funds may be frozen or lost. Lock-up periods add liquidity risk: a 90-day lock that prevents withdrawal during a crisis is a serious cost disguised as a feature. Diversifying across two or three platforms and stablecoins reduces single-platform risk, but it does not remove the systemic risk that a market-wide crash hits all of them simultaneously.

A practical checklist helps. Ask where the yield comes from and whether it survives if the platform's token falls 50 percent. Check the stablecoin's reserve reporting and redemption history. Check the protocol's audit history and total value locked trend, because rapidly falling deposits often precede trouble. Compare the yield against comparable platforms: an outlier paying double the market rate is either taking double the risk or subsidising temporarily, and neither is a durable advantage. Finally, size your allocation so that a total loss of that position hurts but does not ruin you; many experienced DeFi users cap any single yield strategy at five to ten percent of their portfolio.

High stablecoin yields are not inherently scams, and many legitimate strategies pay attractive rates, but the rate itself is information: the higher it is, the more risk you are being paid to hold. Treat yield as compensation for specific, nameable risks, verify each one, and diversify. The investors who survived past yield collapses were rarely the ones earning the highest rates; they were the ones who asked where the rate came from and walked away when the answer did not add up.

Before chasing a stablecoin yield, ask where it comes from, what happens if the token or peg fails, and whether you could survive losing the whole allocation. A sustainable six percent from transparent lending beats a subsidised twenty percent that vanishes with the next market shock, and the difference is only visible to those who check.