How Arbitrage Rebalances Prices Across Token Pools

Arbitrage helps align prices across token pools by buying a token where it is cheaper and selling it where it is more expensive. A pool holds reserves of two tokens and uses them to quote trades. In a common automated market maker, a trade changes those reserves, which changes the next quoted price. An arbitrageur compares that quote with prices in other pools or markets, then decides whether a trade can cover its costs.

How does arbitrage change a pool’s price?

In a simple constant-product pool, the reserves of two tokens multiply to a fixed value as trades happen. If someone buys token A with token B, the pool gives up some A and takes in B. A becomes scarcer in that pool, so its quoted price in B rises. The formula sets the pool’s trading curve; it does not tell the pool what A should be worth elsewhere.

Suppose another pool offers A for less B. An arbitrageur can buy A in the cheaper pool and sell it in the dearer one. The first trade pushes the cheap pool’s quote up; the second pushes the expensive pool’s quote down. This is like shoppers moving goods between two stalls until the price gap narrows, though here each trade also changes the stalls’ reserves.

The mechanics behind a particular exchange can differ. For a fuller look at one example, see blackhole swap, which explains how an Avalanche token exchange works. The same broad arbitrage logic applies when traders compare its pool quotes with other venues.

Why do token pool prices drift apart?

Each pool updates its quote only when a trade reaches it. A price move elsewhere does not automatically change the reserves on chain. The gap can last until a trader, bot or other participant notices it and submits a transaction. Different pools may also use different pricing curves, fees and token pairs, so their quotes need not match at every trade size.

Arbitrage is usually considered across a whole route, not just two displayed prices. A trader may swap through several pools to turn one token into another, then compare the result with a direct route or an external market. The route only makes sense if the expected proceeds exceed the input after costs.

What limits arbitrage between pools?

Trading against a gap changes the price as the trade moves through each pool. This price impact can eat into the apparent profit, especially when reserves are small or the trade is large. Pool fees, network fees and competition from other traders also reduce the amount left over. A displayed quote is therefore not a promise that the full trade can execute at that price.

• Pool fee: each swap may charge a fee that narrows the gap’s value.
• Price impact: the trade moves the pool quote while it executes.
• Transaction costs: network fees count even if a route touches multiple pools.
• Execution delay: another trade can close the gap before a transaction lands.

Arbitrage can bring pool quotes closer, but it does not guarantee identical prices. Gaps can remain when they are too small to cover costs, or when trading is slow. For readers comparing routes, the useful figure is the expected amount received after fees and price impact, not the headline price shown by one pool.