Let’s go through an example of how impermanent loss may look like for a liquidity provider.
Alice deposits 1 ETH and 100 DAI in a liquidity pool. In this particular automated market maker (AMM), the deposited token pair needs to be of equivalent value. This means that the price of ETH is 100 DAI at the time of deposit. This also means that the dollar value of Alice’s deposit is 200 USD at the time of deposit.
In addition, there’s a total of 10 ETH and 1,000 DAI in the pool – funded by other LPs just like Alice. So, Alice has a 10% share of the pool, and the total liquidity is 10,000.
If ETH is now 400 DAI, the ratio between how much ETH and how much DAI is in the pool has changed. There is now 5 ETH and 2,000 DAI in the pool, thanks to the work of arbitrage traders.
So, Alice decides to withdraw her funds. As we know from earlier, she’s entitled to a 10% share of the pool. As a result, she can withdraw 0.5 ETH and 200 DAI, totaling 400 USD. She made some nice profits since her deposit of tokens worth 200 USD, right? But wait, what would have happened if she simply holds her 1 ETH and 100 DAI? The combined dollar value of these holdings would be 500 USD now.
With that said, Alice’s example completely disregards the trading fees she would have earned for providing liquidity. In many cases, the fees earned would negate the losses and make providing liquidity profitable nevertheless. Even so, it’s crucial to understand impermanent loss before providing liquidity to a DeFi protocol.