An automated market maker allows trades against a pool of assets whose contract calculates prices from balances and a formula. It replaces the need for a dealer to accept each order, but it does not discover an objectively correct price or guarantee that enough assets remain for every trade size.
The mechanism matters because every swap changes the pool. Traders receive immediate execution under known rules, liquidity providers earn the stated fees, and outside arbitrageurs trade when the pool differs from other markets. Those same adjustments can leave providers with a less valuable asset mix than simply holding their original tokens.
What you will learn
- Explain how a constant-product pool produces a changing price
- Describe the role of arbitrage in aligning pool and external markets
- Calculate the economic meaning of divergence loss
- Identify who pays fees and who bears pool losses
Pricing from pool balances
Consider a pool containing two tokens. A common design requires the product of the two balances to remain approximately constant after accounting for fees. When a trader adds one token and removes the other, the removed token becomes scarcer inside the pool, so each additional unit costs progressively more.
This curve creates continuous quotes without an order book. It also creates price impact: the average execution rate worsens as a trade consumes more of the available side. Different AMM designs use different curves or concentrate liquidity within selected ranges, but all must define how inventory changes translate into executable prices.
How external prices reach the pool
The AMM formula sees only its balances and incoming transactions. It does not read company accounts, news, or a universal price feed. When Token X trades elsewhere at a different price, arbitrageurs can buy from the cheaper venue and sell to the more expensive one until costs and risks erase the opportunity.
Arbitrage updates the pool through trades, transferring value in the process. If X rises elsewhere, arbitrageurs may remove X from the pool and add stablecoins. Liquidity providers then own less of the rising asset and more of the other asset. The pool follows the outside market because someone profits from correcting it, not because the formula knows truth.
Fees, inventory, and divergence
Traders pay pool fees, which accrue to liquidity according to the protocol's accounting. That revenue compensates providers for supplying inventory and accepting contract, execution, and asset risks. More volume can mean more gross fees, but volume caused by volatile repricing can also accompany larger changes in the provider's asset composition.
Divergence loss compares the value of the pooled position with the value of holding the same starting assets outside the pool at current market prices. It is often called impermanent loss, but the word impermanent can mislead: withdrawing crystallizes the difference, and prices may never return. Fees can offset it, but no rule guarantees that they will.
Protocol design and user interface
The protocol specifies the curve, fee allocation, liquidity ranges, and methods for adding or removing assets. Governance may be able to enable fee settings or approve deployments, depending on the design. The interface estimates positions and routes, but its annualized fee display is not an enforceable promise from the underlying contracts.
Evaluation should examine the exact pool, token contracts, active liquidity, trading volume, fee tier, and provider position range. Concentrated liquidity can improve capital efficiency when prices remain in range, yet stop earning fees outside that range and create active management demands. A familiar AMM brand does not make every pool equally liquid or safe.
Common misconceptions
“An AMM calculates the true economic value of each token.”
An AMM calculates a trade price from its formula and balances. External information reaches the pool through traders and arbitrage, whose activity has costs and transfers value.
“Impermanent loss disappears as long as the liquidity provider waits long enough.”
The comparison changes with relative prices and fees, but no waiting period ensures recovery. Withdrawal realizes the current asset mix, and a previous price relationship may never return.
Risks and limitations
- Divergence risk: relative price changes can make the pooled position worth less than holding the original asset quantities.
- Smart-contract risk: defects in pool, router, or accounting code can cause incorrect execution, frozen funds, or theft.
- Asset risk: a token can depeg, freeze transfers, impose taxes, or lose most of its market value while remaining in the pool.
- Range and liquidity risk: concentrated positions can stop earning fees and become heavily composed of the weaker-performing asset.
Key takeaways
- AMMs quote from programmed curves and current inventory rather than an independent view of fair value.
- Larger trades move pool balances further and generally incur greater price impact.
- Arbitrage aligns pools with external markets while changing provider inventory.
- Trading fees are real revenue, but they do not guarantee profit after divergence and other losses.
- Protocol parameters and interface estimates should be reviewed separately.
Primary and further reading
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