Why does a stablecoin swap rate show 0.997 instead of exactly 1

05 September 2026

Because the swap rate you see is not the exchange rate between two stablecoins; it is the exchange rate minus the cost of moving value across a chain, a liquidity pool, or a bridge. That 0.3% gap is the price of the operation, not a mistake.

Stablecoins are supposed to trade at 1:1. In practice, the quoted rate of 0.997 means you receive 99.7 units of the target stablecoin for every 100 units you send. The missing 0.3% is not a single fee. It is the sum of several small costs, and which ones apply depends on the route.

The largest and most predictable component is the liquidity provider fee. When you swap one stablecoin for another on a decentralised exchange, you are trading against a pool of funds. That pool charges a small percentage on every trade, typically 0.3% for standard pools or 0.05% for stablecoin-specialised pools. The pool charges this regardless of whether the two assets are nominally worth the same. The rate you see is computed after that fee is taken out, so a 1.000 rate becomes 0.997.

There is also the spread. A pool does not quote a single price. It quotes a range based on the ratio of the two assets in it. If the pool has slightly more of one token than the other, the effective price of the less abundant token drifts above 1. That drift is baked into the rate you see. The 0.997 may include a tiny market imbalance, not just a fee.

Bridges add another layer. If you are moving a stablecoin from one chain to another, the swap rate often reflects the bridge's cost and its own liquidity reserves. A bridge that holds both sides of the token pair will quote a rate that covers its operational expenses. It may also include a small buffer against slippage, because the bridge must guarantee a payout even if the underlying pool moves while your transaction is pending.

Finally, the rate shown is often a mid-point, not what you actually receive. Some interfaces display the rate before a variable network fee is subtracted. On congested chains, the gas fee can be significant relative to a small swap. If you swap 100 USDC and pay 0.30 in gas, your effective rate is 0.997 even if the pool fee was only 0.05%. The displayed number may or may not include that gas; if it does not, the final settlement will be worse than the quote.

There is a second reason you might see 0.997 that has nothing to do with fees. Some stablecoins are not perfectly pegged. A token like USDT or USDC can trade at a slight discount or premium on a particular chain, because demand for that token on that chain differs from demand elsewhere. If the chain you are swapping on has a temporary surplus of one stablecoin, the rate will reflect that surplus. The gap is usually small, but it is real and it moves.

The practical takeaway is this: 0.997 is not a failure of the system. It is the cost of doing business. If you see a rate of exactly 1.000, that is the anomaly. It usually means the platform is subsidising the swap, or the quote is stale. A stablecoin swap that shows 1.000 is either a promotion or a trap.

If you are moving between volatile assets and stablecoins, or between stablecoins on different chains, expect that small gap every time. The hub page on swapping into and out of stablecoins covers the broader mechanics, including how to minimise the gap by choosing the right route. But the short answer to the 0.997 question is simple: the rate you see is the net rate after costs, and those costs are never zero.

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