Uniswap Labs has launched StablePair Hook, a Uniswap v4 tool that sets liquidity-provider fees dynamically for two stable-pair pools on Ethereum instead of charging a single constant rate.
The initial rollout covers USDC/USDT and USDC/USDG.
How the fee model changes when a pool moves off target
For liquidity providers, the main shift appears when a pool drifts away from its expected rate. Uniswap said corrective trades outside a configured price band are auctioned through a fee that falls each block until someone accepts it. The pool keeps the fee charged at execution, which lets it capture part of the arbitrage opportunity as revenue.
In a fixed-fee stable-pair pool, the same percentage applies whether the assets are close to parity or have already diverged. Uniswap framed the tradeoff this way: a low fee leaves more of the corrective spread to arbitrageurs, while a high fee can make the pool’s quotes less competitive.
Fees depend on price location and trade direction
StablePair sets each pool with a reference rate and a narrow band around that rate. The hook then determines the LP fee from three inputs: the pool price, the distance from the reference rate, and the direction of the proposed trade.
Inside the band, the fee changes to maintain consistent pre-price-impact buy and sell quotes. At the reference rate, trades in both directions pay the configured band width. Near an edge, the fee for a trade that pushes the pool toward that edge drops toward zero, while the fee in the opposite direction rises toward roughly twice the band width.
Outside the band, a trade that pushes the pool even farther from the reference rate pays no fee because it is not extracting the existing mispricing. A corrective trade, by contrast, faces a fee that starts at the far edge of the band and decays once per block until someone takes it. The pool collects the fee charged when the trade executes.
Price impact still applies
The mechanism does not remove price impact. The fee is independent of swap size, and Uniswap’s documentation says a large trade can still move along the pool’s pricing curve and end up with a worse average price than a smaller one.
Launch is limited to two Ethereum pools
Uniswap said stablecoin-to-stablecoin swaps on its protocol totaled $43.4 billion in the second quarter. For now, StablePair is limited to the two Ethereum pools, and only Uniswap Labs can create pools against the hook.
Pool parameters and fee logic can be changed through Uniswap governance without requiring liquidity to migrate to a new pool.