AMM และกลุ่มสภาพคล่อง

Decentralized Finance (DeFi) has revolutionized how we trade assets. At its heart are Automated Market Makers (AMMs).

AMMs power decentralized exchanges (DEXs) like Uniswap, allowing users to swap tokens without traditional buyers and sellers.

Instead of matching orders, AMMs use mathematical formulas and liquidity pools.

Traditional exchanges use order books, where buyers and sellers list their desired prices. Trades only happen when bids and asks match.

• Order Books: Centralized, requires matching orders, can suffer from low liquidity.
• AMMs: Decentralized, uses liquidity pools, always offers a price determined by a formula.

AMMs solve the liquidity problem for many token pairs on a blockchain by always providing a market.

An AMM's backbone is the liquidity pool. This is a collection of two or more tokens locked in a smart contract.

For example, a common pool might hold ETH and a stablecoin like DAI. Users can swap between these tokens directly from the pool.

These pools are funded by individuals called Liquidity Providers (LPs).

Most AMMs, like Uniswap, use the constant product formula: x * y = k.

• x is the quantity of the first token.
• y is the quantity of the second token.
• k is a constant product that must remain unchanged after a trade.

When you swap tokens, the quantities of x and y change, but their product k stays the same, determining the new price ratio.

Liquidity Providers (LPs) deposit an equal value of two tokens into a liquidity pool. For example, $1000 worth of ETH and $1000 worth of DAI.

In return, LPs receive Liquidity Pool (LP) tokens. These tokens represent their share of the pool.

LP tokens can be redeemed later to withdraw your original deposit plus any accumulated fees.

When an LP adds liquidity, they increase the total supply of x and y in the pool, which also increases the constant k.

The AMM smart contract ensures that tokens are added in the correct ratio to maintain the pool's balance and prevent immediate price changes.

This process makes the pool deeper, allowing for larger trades with less price impact.

When a user wants to swap Token A for Token B, they send Token A to the liquidity pool.

The AMM's smart contract then calculates how much Token B to give back, based on the x * y = k formula.

The pool's balance shifts, and the price of the tokens adjusts automatically according to the formula.

Let's see a simplified Solidity contract that simulates how an AMM might perform a swap using the constant product formula.

This example demonstrates the core calculation and reserve update.

One major risk for LPs is impermanent loss. This occurs when the price of the assets in the liquidity pool changes relative to when you deposited them.

If the price ratio diverges significantly, the value of your tokens withdrawn from the pool might be less than if you had simply held them outside the pool.

It's called "impermanent" because the loss only becomes permanent if you withdraw your liquidity before the prices return to their original ratio.

Despite impermanent loss, LPs are incentivized by earning a share of the trading fees generated by the pool.

Each time a trade occurs, a small percentage (e.g., 0.3%) of the swapped amount is added to the liquidity pool.

These fees accumulate in the pool and are distributed proportionally to LPs when they withdraw their liquidity, compensating them for providing capital and taking on impermanent loss risk.

We've explored how Automated Market Makers (AMMs) provide decentralized trading by using liquidity pools instead of traditional order books.

Key takeaways:

• AMMs use formulas like x * y = k to determine prices.
• Liquidity Providers (LPs) fund pools and earn trading fees.
• Impermanent loss is a risk for LPs due to price divergence.

Understanding these concepts is vital for navigating the DeFi landscape!