Liquidity Pool

A liquidity pool is a collection of cryptocurrency tokens locked in a smart contract that provides the liquidity needed for decentralized exchanges (DEXs) and other DeFi protocols to function. Instead of the traditional order book model used by centralized exchanges (where buyers and sellers are directly matched), DEXs use liquidity pools and automated market makers (AMMs) to facilitate trades algorithmically.

In a typical DEX liquidity pool (like those on Uniswap), two tokens are paired together in a specific ratio (usually 50/50 by value). Liquidity providers (LPs) deposit equal values of both tokens into the pool and receive LP tokens representing their share. When traders swap between the two tokens, the pool's smart contract automatically adjusts prices based on the constant product formula (x × y = k), where the product of the two token quantities remains constant. Larger pools offer lower slippage (price impact) for traders.

Liquidity providers earn a share of trading fees (typically 0.3% of each swap on Uniswap) proportional to their pool share. However, LPs face a unique risk called impermanent loss — when the price ratio of the pooled tokens changes relative to their initial deposit ratio, LPs end up with fewer of the appreciating token and more of the depreciating one compared to simply holding. This loss is "impermanent" because it disappears if prices return to their original ratio, but becomes permanent upon withdrawal. Concentrated liquidity (introduced in Uniswap V3) allows LPs to provide liquidity within specific price ranges, improving capital efficiency but requiring more active management.