Uniswap Labs has introduced StablePair Hook, a dynamic-fee mechanism built for Uniswap v4 that targets stable pairs such as USDC/USDT and similar assets. The feature went live on Ethereum mainnet on September 10, 2026, with initial pools for USDC/USDG and USDC/USDT.

Stable pairs rank among the highest-volume markets in decentralized finance. Stablecoin-to-stablecoin swaps on the Uniswap Protocol alone totaled $43.4 billion in the second quarter of 2026, exceeding the combined volume of the next three onchain venues.

How the Dynamic Fee System Operates

Traditional static fees on stable pairs often allow arbitrage activity to capture most of the value when prices drift from parity. A low fixed fee leaves the spread to bots, while a high fee can make the pool uncompetitive.

StablePair Hook replaces the fixed rate with a dynamic fee calculated on every swap. It measures the pool’s current price against a reference rate and adjusts accordingly.

Within a tight band around the reference rate, the fee changes with each trade to maintain a consistent bid-ask spread. At the exact reference rate, both directions incur the same fee equal to the band width. As the price approaches one edge, the fee for trades pushing further toward that edge declines toward zero, while the opposite direction rises toward roughly twice the band width.

Once the price moves outside the band, the logic shifts. Trades that drive the price farther from the reference rate incur no fee, since they introduce no existing mispricing for the pool to extract. Corrective trades that restore the price toward parity enter a Dutch auction structure. The fee begins high and declines with each block until a trader accepts it. Liquidity providers retain the resulting difference as fee revenue.

The fee remains independent of trade size, so larger swaps can still generate price impact along the pool’s curve.

Upgrade Path and Initial Scope

StablePair Hook is designed for ongoing refinement. Pool parameters and fee logic can be updated through Uniswap Governance without requiring liquidity providers to migrate capital to new pools. This marks it as an upgradeable dynamic-fee hook from Uniswap Labs.

At launch, only Uniswap Labs can create new pools using the hook. The two live Ethereum pools serve as the starting point, with the mechanism intended for broader stable pairs over time, including examples such as WBTC/cbBTC.

The tool joins earlier Uniswap Labs hooks, including DualPool, Permissioned Pools, and LitePSM. Hooks as a category have already facilitated substantial activity on Uniswap v4, with more than 90,000 instances initialized across multiple chains.

Context Within Uniswap Protocol

Uniswap Labs serves as a core contributor to the Uniswap Protocol, which has processed more than $4.6 trillion in total trading volume. The company also develops supporting products such as the Uniswap Web App, Wallet, and API.

By allowing individual pools to define custom rules, fees, and pricing logic, hooks expand the flexibility of the automated market maker model beyond the original design that opened decentralized trading to a wide range of assets.

Liquidity providers can move capital into the new USDC/USDG and USDC/USDT pools, while traders can access them through existing Uniswap interfaces. Issuers and developers have access to documentation for building related custom hooks.